CVE-2026-94184

A stack-based buffer overflow flaw was found in fetchmail when built with NTLM support. A malicious or compromised mail server advertising NTLM authentication can send a crafted Type 2 challenge that causes fetchmail to write past a fixed stack buffer while building the NTLM authenticate response. This may lead to remote code execution depending on stack-frame layout, or to authentication failure or process termination under memory hardening.

• https://access.redhat.com/errata/RHSA-2026:85959
• https://access.redhat.com/errata/RHSA-2026:86981
• https://access.redhat.com/errata/RHSA-2026:86982
• https://access.redhat.com/security/cve/CVE-2026-94184
• https://bugzilla.redhat.com/show_bug.cgi?id=2531984
• https://bugzilla.redhat.com/show_bug.cgi?id=2537395
• https://gitlab.com/fetchmail/fetchmail/-/commit/cb5be5c38471eec19e519ace0bc569176317ea92
• https://www.fetchmail.info/fetchmail-SA-2026-01.txt
• https://www.openwall.com/lists/oss-security/2026/06/27/8
• http://www.openwall.com/lists/oss-security/2026/09/23/1