Updated 3 h ago

Vulnerability database

Every flaw the U.S. government’s cybersecurity agency (CISA) has confirmed attackers are using, plus the new WordPress plugin and theme bugs published each day, sorted by what they mean for a small business. We refresh it twice a day. If you see something your website or office runs, tell us.

1,762exploited flaws on CISA’s list

34added in the last 30 days

333new WordPress flaws this week

390,007entries in the database

1,097 results · page 1 of 22

Oct 27, 2026When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server's login response without validating it.CVE-2026-118180 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server's login response without validating it. A malicious or compromised homeserver could provide a file: URL, causing Thunderbird to send all further Matrix requests of that session to local files or, on Windows, to an attacker-controlled network share, which could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 27, 2026Clicking a news: or snews: link that referenced a message-ID made Thunderbird connect, without asking, to the host and port given in the link, even if it was noCVE-2026-118179 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
Clicking a news: or snews: link that referenced a message-ID made Thunderbird connect, without asking, to the host and port given in the link, even if it was not a configured news server. Line breaks in the message-ID were sent to the server unmodified, so a crafted link could send arbitrary commands to services reachable from the user's network. In addition, snews: links to such servers connected without TLS. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 27, 2026A remote RSS feed could use the itunes:new-feed-url or newLocation element to permanently change its stored subscription URL to a file: URL.CVE-2026-118178 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
A remote RSS feed could use the itunes:new-feed-url or newLocation element to permanently change its stored subscription URL to a file: URL. Thunderbird then read that location on every feed update. This allowed a malicious feed, or an attacker able to modify a feed delivered over HTTP, to make Thunderbird read local files and, on Windows, connect to an attacker-controlled network share, which could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are affected by the local file read only. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 27, 2026When looking for calendars in a directory on a server, during account setup or when adding a new network calendar, Thunderbird accepted calendar locations pointCVE-2026-118177 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
When looking for calendars in a directory on a server, during account setup or when adding a new network calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's share or overwrite a local file. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 27, 2026Thunderbird's check that prevents mailbox: URLs from accessing files on remote Windows network shares could be bypassed using extended-length UNC paths.CVE-2026-118176 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
Thunderbird's check that prevents mailbox: URLs from accessing files on remote Windows network shares could be bypassed using extended-length UNC paths. Displaying a specially crafted email could cause Thunderbird to connect to an SMB server chosen by the attacker, disclosing the user's Windows account name and NTLM authentication data, which could be used for offline password cracking or relay attacks. This bug only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 27, 2026When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of a different message stored in the same folder into theCVE-2026-118175 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of a different message stored in the same folder into the message being composed, without showing a blocked content warning. If the user sent the message, the content of the other message was disclosed to the recipients. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 27, 2026When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key.CVE-2026-118174 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
When a message containing an OpenPGP key attachment was displayed, Thunderbird automatically loaded the attachment's content to offer importing the key. A sender could mark the attachment as an external attachment pointing to an arbitrary URL, which Thunderbird then loaded without any user interaction, bypassing remote content blocking. On Windows, a URL pointing to an attacker-controlled network share could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. On other operating systems, the issue allowed a remote request that bypassed remote content blocking. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 20, 2026When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary Password) while decrypting an S/MIME message, the message loadCVE-2026-113869 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 5.4
When Thunderbird asked for a security device password (for example a smartcard PIN or the Primary Password) while decrypting an S/MIME message, the message load could finish or be cancelled while the prompt was open. This freed the message decoder while it was still in use, causing a use-after-free and a potentially exploitable crash. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 20, 2026When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's challenge was valid base64.CVE-2026-113868 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 5.3
When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only affected NTLM. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 20, 2026Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas.CVE-2026-113867 · Computers, phones & browsers · Mozilla · reported by security@mozilla.org
Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas. Because values from incoming requests were echoed back in automatic replies, a remote XMPP user could send a crafted request that caused Thunderbird to inject arbitrary stanzas into the user's connection, which the server would then process as if sent by the user. This could be used to send messages or change contact and subscription settings on behalf of the user, without any interaction. This bug only affects Thunderbird's chat feature with XMPP accounts. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 20, 2026When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's AutoDiscover service over plain HTTP.CVE-2026-113866 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 5.9
When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the user had entered, allowing a network attacker to obtain the user's password. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 13, 2026A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep CVE-2026-110249 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.6
A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Oct 13, 2026Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks.CVE-2026-110247 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.4
Several buffer-growth sites in libmime performed size arithmetic in 32-bit types without overflow checks. On a sufficiently large message the growth guard could fail open, or the buffer could be reallocated smaller than required, and a subsequent memcpy would then write attacker-controlled data across adjacent heap allocations. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.6.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 30, 2026An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size.CVE-2026-103500 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 6.1
An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Information disclosure in the Networking component.CVE-2026-96869 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 4.3
Information disclosure in the Networking component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Privilege escalation in the Address Bar component.CVE-2026-100820 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Privilege escalation in the Address Bar component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Sandbox escape due to use-after-free in the Widget: Gtk component.CVE-2026-100818 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.6
Sandbox escape due to use-after-free in the Widget: Gtk component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Other issue in the JavaScript: WebAssembly component.CVE-2026-100817 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 5.4
Other issue in the JavaScript: WebAssembly component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Invalid pointer in the JavaScript Engine: JIT component.CVE-2026-100813 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Invalid pointer in the JavaScript Engine: JIT component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Sandbox escape due to use-after-free in the DOM: Core & HTML component.CVE-2026-100811 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.6
Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Other issue in the DevTools component.CVE-2026-100810 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.8
Other issue in the DevTools component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Privilege escalation in the DOM: Service Workers component.CVE-2026-100807 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Privilege escalation in the DOM: Service Workers component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Race condition, use-after-free in the Audio/Video component.CVE-2026-100805 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 7.5
Race condition, use-after-free in the Audio/Video component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Sandbox escape due to use-after-free in the Preferences: Backend component.CVE-2026-100804 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.6
Sandbox escape due to use-after-free in the Preferences: Backend component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Uninitialized memory in the Graphics: WebGPU component.CVE-2026-100802 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 4.3
Uninitialized memory in the Graphics: WebGPU component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Privilege escalation in the DLL Services component.CVE-2026-100801 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Privilege escalation in the DLL Services component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 159, Firefox ESR 153.6, Thunderbird 159, Thunderbird 153.6, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Uninitialized memory in the Graphics: WebGPU component.CVE-2026-100799 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 4.3
Uninitialized memory in the Graphics: WebGPU component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Use-after-free in the JavaScript: WebAssembly component.CVE-2026-100796 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Denial-of-service in the Networking component.CVE-2026-100795 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 6.5
Denial-of-service in the Networking component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Sandbox escape due to incorrect boundary conditions in the Internationalization component.CVE-2026-100794 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.6
Sandbox escape due to incorrect boundary conditions in the Internationalization component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026JIT miscompilation in the JavaScript Engine component.CVE-2026-100793 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgMedium 6.5
JIT miscompilation in the JavaScript Engine component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026JIT miscompilation in the JavaScript: WebAssembly component.CVE-2026-100792 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 7.1
JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Invalid pointer in the JavaScript: WebAssembly component.CVE-2026-100788 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.8
Invalid pointer in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Use-after-free in the JavaScript: WebAssembly component.CVE-2026-100776 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Use-after-free in the DOM: Core & HTML component.CVE-2026-100772 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Use-after-free in the JavaScript: WebAssembly component.CVE-2026-100769 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Use-after-free in the Graphics: WebGPU component.CVE-2026-100768 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Use-after-free in the Graphics: WebGPU component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Privilege escalation due to incorrect boundary conditions in the Graphics: WebGPU component.CVE-2026-100764 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Privilege escalation due to incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Incorrect boundary conditions in the Graphics: WebGPU component.CVE-2026-100763 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.1
Incorrect boundary conditions in the Graphics: WebGPU component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 29, 2026Privilege escalation due to use-after-free in the Graphics: WebGPU component.CVE-2026-100761 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.8
Privilege escalation due to use-after-free in the Graphics: WebGPU component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 15, 2026A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing ThunderbirCVE-2026-92240 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.1
A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 15, 2026A maliciously constructed IMAP line could cause an out-of-bounds buffer read.CVE-2026-92239 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 8.1
A maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 15, 2026A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations.CVE-2026-92238 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.8
A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 1, 2026The values of the mail.allowed_attachment_hostnames advanced config setting were used in a regular expression without escaping.CVE-2026-84642 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 7.5
The values of the mail.allowed_attachment_hostnames advanced config setting were used in a regular expression without escaping. For some possible valid hostnames, this could allow certain unintended hostnames to also match and serve remote attachments. This vulnerability was fixed in Thunderbird 155 and Thunderbird 153.2.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 1, 2026A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response.CVE-2026-84641 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 7.5
A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 1, 2026A maliciously constructed mail header could lead to a one byte read past the end of a buffer.CVE-2026-84640 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 7.5
A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 1, 2026Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used.CVE-2026-84639 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.1
Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 1, 2026Malicious calendar invitations could use file URI attachments to launch local or network-hosted executables on Windows, bypassing Thunderbird's normal executablCVE-2026-84637 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgCritical 9.8
Malicious calendar invitations could use file URI attachments to launch local or network-hosted executables on Windows, bypassing Thunderbird's normal executable attachment protections. With the new invitation display enabled, the attachment could also appear under a misleading filename. This vulnerability was fixed in Thunderbird 154 and Thunderbird 153.2.
Product
Thunderbird
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org mozilla.org
Sep 1, 2026Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14.CVE-2026-84145 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 7.5
Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Product
Firefox
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org bugzilla.mozilla.org
Sep 1, 2026Internally found bugs present in Thunderbird 154 and Thunderbird ESR 153.1.CVE-2026-84144 · Computers, phones & browsers · Mozilla · reported by security@mozilla.orgHigh 7.5
Internally found bugs present in Thunderbird 154 and Thunderbird ESR 153.1. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
Product
Firefox
What to do
Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD record bugzilla.mozilla.org bugzilla.mozilla.org

Where this comes from: the exploited list is CISA’s Known Exploited Vulnerabilities catalog. Everything else is the whole National Vulnerability Database, where each record is published by the team that found the bug (Wordfence, Patchstack, WPScan, the vendors themselves and others); we show who. Exploit odds are FIRST’s EPSS, updated daily. Titles and categories are ours, so check the linked record before acting on a detail. For a write-up of the big ones, see our advisories. Every vendor, and every WordPress plugin and theme with a recorded flaw, also has its own page. All of it is free to reuse as JSON, CSV or RSS.

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