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.
19 results
Sep 18, 2026c-ares is an asynchronous resolver library.CVE-2026-69186 · Other software · c-ares · reported by GitHubMedium 5.3
c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_parse() trusts the attacker-controlled ANCOUNT, NSCOUNT, and ARCOUNT fields before confirming that the DNS response contains enough bytes for the claimed records. Because process_answer() invokes parsing before transaction ID and question validation, a malicious DNS response can cause ares_dns_record_rr_prealloc() and ares_array_set_size() to reserve disproportionate heap memory for a tiny message. Repeated responses create large allocation and release cycles that can degrade or deny name resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Sep 18, 2026c-ares is an asynchronous resolver library.CVE-2026-69184 · Other software · c-ares · reported by GitHubHigh 7.5
c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_name_parse() enforces backward DNS compression pointers but does not bound the total pointer hops or assembled name length. A malicious DNS server can send a response containing a long descending pointer chain and many resource records whose NAME or RDATA fields refer to the chain, causing repeated decompression work that grows quadratically with message size. A single crafted response can stall the single-threaded c-ares event loop and deny DNS resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Sep 3, 2026c-ares is an asynchronous resolver library.CVE-2026-33630 · Other software · c-ares · reported by GitHubHigh 7.5
c-ares is an asynchronous resolver library. From ver 1.32.3 until 1.34.7, a use-after-free / double-free in c-ares' query-completion handling. The same flaw — a query's callback being invoked while the query is still linked in the channel's internal lookup structures — is present at multiple points in the resend/finish path (timeout handling, response handling, and query dispatch). If the query, or for ares_getaddrinfo() the owning host_query, is freed as a side effect of that callback, it is then accessed and/or freed a second time. This vulnerability is fixed in ver 1.34.7.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Dec 8, 2025c-ares is an asynchronous resolver library.CVE-2025-62408 · Other software · c-ares · reported by GitHubMedium 5.9
c-ares is an asynchronous resolver library. Versions 1.32.3 through 1.34.5 terminate a query after maximum attempts when using read_answer() and process_answer(), which can cause a Denial of Service. This issue is fixed in version 1.34.6.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Jun 20, 2025pycares is a Python module which provides an interface to c-ares.CVE-2025-48945 · Other software · aio-libs · reported by GitHubHigh 8.2
pycares is a Python module which provides an interface to c-ares. c-ares is a C library that performs DNS requests and name resolutions asynchronously. Prior to version 4.9.0, pycares is vulnerable to a use-after-free condition that occurs when a Channel object is garbage collected while DNS queries are still pending. This results in a fatal Python error and interpreter crash. The vulnerability has been fixed in pycares 4.9.0 by implementing a safe channel destruction mechanism.
- Product
- aiodns
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Apr 8, 2025c-ares is an asynchronous resolver library.CVE-2025-31498 · Other software · c-ares · reported by GitHubHigh 8.3
c-ares is an asynchronous resolver library. From 1.32.3 through 1.34.4, there is a use-after-free in read_answers() when process_answer() may re-enqueue a query either due to a DNS Cookie Failure or when the upstream server does not properly support EDNS, or possibly on TCP queries if the remote closed the connection immediately after a response. If there was an issue trying to put that new transaction on the wire, it would close the connection handle, but read_answers() was still expecting the connection handle to be available to possibly dequeue other responses. In theory a remote attacker might be able to trigger this by flooding the target with ICMP UNREACHABLE packets if they also control the upstream nameserver and can return a result with one of those conditions, this has been untested. Otherwise only a local attacker might be able to change system behavior to make send()/write() return a failure condition. This vulnerability is fixed in 1.34.5.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Feb 23, 2024c-ares is a C library for asynchronous DNS requests.CVE-2024-25629 · Other software · c-ares · reported by GitHubMedium 4.4
c-ares is a C library for asynchronous DNS requests. `ares__read_line()` is used to parse local configuration files such as `/etc/resolv.conf`, `/etc/nsswitch.conf`, the `HOSTALIASES` file, and if using a c-ares version prior to 1.27.0, the `/etc/hosts` file. If any of these configuration files has an embedded `NULL` character as the first character in a new line, it can lead to attempting to read memory prior to the start of the given buffer which may result in a crash. This issue is fixed in c-ares 1.27.0. No known workarounds exist.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Aug 22, 2023Buffer overflow vulnerability in c-ares before 1_16_1 thru 1_17_0 via function ares_parse_soa_reply in ares_parse_soa_reply.c.CVE-2020-22217 · Other software · C-ares · reported by MITREMedium 5.9
Buffer overflow vulnerability in c-ares before 1_16_1 thru 1_17_0 via function ares_parse_soa_reply in ares_parse_soa_reply.c.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD recordgithub.comlists.debian.org
May 25, 2023c-ares is an asynchronous resolver library.CVE-2023-32067 · Other software · c-ares · reported by GitHubHigh 7.5
c-ares is an asynchronous resolver library. c-ares is vulnerable to denial of service. If a target resolver sends a query, the attacker forges a malformed UDP packet with a length of 0 and returns them to the target resolver. The target resolver erroneously interprets the 0 length as a graceful shutdown of the connection. This issue has been patched in version 1.19.1.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
May 25, 2023c-ares is an asynchronous resolver library.CVE-2023-31147 · Other software · c-ares · reported by GitHubMedium 5.9
c-ares is an asynchronous resolver library. When /dev/urandom or RtlGenRandom() are unavailable, c-ares uses rand() to generate random numbers used for DNS query ids. This is not a CSPRNG, and it is also not seeded by srand() so will generate predictable output. Input from the random number generator is fed into a non-compilant RC4 implementation and may not be as strong as the original RC4 implementation. No attempt is made to look for modern OS-provided CSPRNGs like arc4random() that is widely available. This issue has been fixed in version 1.19.1.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
May 25, 2023c-ares is an asynchronous resolver library.CVE-2023-31130 · Other software · c-ares · reported by GitHubMedium 4.1
c-ares is an asynchronous resolver library. ares_inet_net_pton() is vulnerable to a buffer underflow for certain ipv6 addresses, in particular "0::00:00:00/2" was found to cause an issue. C-ares only uses this function internally for configuration purposes which would require an administrator to configure such an address via ares_set_sortlist(). However, users may externally use ares_inet_net_pton() for other purposes and thus be vulnerable to more severe issues. This issue has been fixed in 1.19.1.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
May 25, 2023c-ares is an asynchronous resolver library.CVE-2023-31124 · Other software · c-ares · reported by GitHubLow 3.7
c-ares is an asynchronous resolver library. When cross-compiling c-ares and using the autotools build system, CARES_RANDOM_FILE will not be set, as seen when cross compiling aarch64 android. This will downgrade to using rand() as a fallback which could allow an attacker to take advantage of the lack of entropy by not using a CSPRNG. This issue was patched in version 1.19.1.
- Product
- c-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Mar 6, 2023A flaw was found in the c-ares package.CVE-2022-4904 · Other software · C-ares Project · reported by Red HatHigh 8.6
A flaw was found in the c-ares package. The ares_set_sortlist is missing checks about the validity of the input string, which allows a possible arbitrary length stack overflow. This issue may cause a denial of service or a limited impact on confidentiality and integrity.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD recordbugzilla.redhat.comgithub.com
Nov 23, 2021A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnCVE-2021-3672 · Other software · C-ares Project · reported by Red HatMedium 5.6
A flaw was found in c-ares library, where a missing input validation check of host names returned by DNS (Domain Name Servers) can lead to output of wrong hostnames which might potentially lead to Domain Hijacking. The highest threat from this vulnerability is to confidentiality and integrity as well as system availability.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD recordbugzilla.redhat.comc-ares.haxx.se
May 13, 2021A possible use-after-free and double-free in c-ares lib version 1.16.0 if ares_destroy() is called prior to ares_getaddrinfo() completing.CVE-2020-14354 · Other software · C-ares · reported by Red HatLow 3.3
A possible use-after-free and double-free in c-ares lib version 1.16.0 if ares_destroy() is called prior to ares_getaddrinfo() completing. This flaw possibly allows an attacker to crash the service that uses c-ares lib. The highest threat from this vulnerability is to this service availability.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD recordbugzilla.redhat.comc-ares.haxx.se
Jul 7, 2017The c-ares function `ares_parse_naptr_reply()`, which is used for parsing NAPTR responses, could be triggered to read memory outside of the given input buffer iCVE-2017-1000381 · Other software · C-ares · reported by MITREHigh 7.5
The c-ares function `ares_parse_naptr_reply()`, which is used for parsing NAPTR responses, could be triggered to read memory outside of the given input buffer if the passed in DNS response packet was crafted in a particular way.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD recordsecurityfocus.comc-ares.haxx.se
Oct 3, 2016Heap-based buffer overflow in the ares_create_query function in c-ares 1.x before 1.12.0 allows remote attackers to cause a denial of service (out-of-bounds wriCVE-2016-5180 · Other software · C-ares · reported by chrome-cve-admin@google.comCritical 9.8
Heap-based buffer overflow in the ares_create_query function in c-ares 1.x before 1.12.0 allows remote attackers to cause a denial of service (out-of-bounds write) or possibly execute arbitrary code via a hostname with an escaped trailing dot.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Full record and what to do →NVD recordrhn.redhat.comdebian.org
Jun 11, 2007The ares_init:randomize_key function in c-ares, on platforms other than Windows, uses a weak facility for producing a random number sequence (Unix rand), which CVE-2007-3153 · Other software · Daniel Stenberg · reported by MITREMedium 5
The ares_init:randomize_key function in c-ares, on platforms other than Windows, uses a weak facility for producing a random number sequence (Unix rand), which makes it easier for remote attackers to spoof DNS responses by guessing certain values.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
Jun 11, 2007c-ares before 1.4.0 uses a predictable seed for the random number generator for the DNS Transaction ID field, which might allow remote attackers to spoof DNS reCVE-2007-3152 · Other software · Daniel Stenberg · reported by MITREHigh 7.5
c-ares before 1.4.0 uses a predictable seed for the random number generator for the DNS Transaction ID field, which might allow remote attackers to spoof DNS responses by guessing the field value.
- Product
- C-ares
- What to do
- Apply the vendor’s update. The NVD record links to the advisory.
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.
Weekly security brief
The flaws that hit local websites, every Friday.
One short email: what got exploited this week, which WordPress plugins broke, and what to check. Unsubscribe in one click.
Tell us what you're building.
A website, your marketing, a security check, an app, or the thing you've been running out of a spreadsheet for three years. A few lines is plenty.
Not ready to talk yet? Run the free website check and see what Google sees.