CVE-2021-3882: LedgerSMB does not set the 'Secure' attribute on the session authorization cookie when the client uses HTTPS and the LedgerSMB server is behind a reverse proxy.

LedgerSMB does not set the 'Secure' attribute on the session authorization cookie when the client uses HTTPS and the LedgerSMB server is behind a reverse proxy.

LedgerSMB does not set the 'Secure' attribute on the session authorization cookie when the client uses HTTPS and the LedgerSMB server is behind a reverse proxy. By tricking a user to use an unencrypted connection (HTTP), an attacker may be able to obtain the authentication data by capturing network traffic. LedgerSMB 1.8 and newer switched from Basic authentication to using cookie authentication with encrypted cookies. Although an attacker can't access the information inside the cookie, nor the password of the user, possession of the cookie is enough to access the application as the user from which the cookie has been obtained. In order for the attacker to obtain the cookie, first of all the server must be configured to respond to unencrypted requests, the attacker must be suitably positioned to eavesdrop on the network traffic between the client and the server *and* the user must be tricked into using unencrypted HTTP traffic. Proper audit control and separation of duties limit Integrity impact of the attack vector. Users of LedgerSMB 1.8 are urged to upgrade to known-fixed versions. Users of LedgerSMB 1.7 or 1.9 are unaffected by this vulnerability and don't need to take action.

Description from the National Vulnerability Database, published by security@huntr.dev

What it means for a small business

If your business uses ledgersmb/ledgersmb, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 1.1%, higher than 66% of CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

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Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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