CVE-2026-45185

Description

Exim before 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path. It is triggered when a client sends a TLS close_notify mid-body during a CHUNKING transfer, followed by a final cleartext byte on the same TCP connection. This can lead to heap corruption. An unauthenticated network attacker exploiting this vulnerability could execute arbitrary code.

CVSS Vector

References

• https://code.exim.org/exim/wiki/wiki/EximSecurity
• https://exim.org
• https://exim.org/static/doc/security/CVE-2026-45185.txt
• https://exim.org/static/doc/security/EXIM-Security-2026-05-01.1/
• https://news.ycombinator.com/item?id=48111748
• https://www.openwall.com/lists/oss-security/2026/05/12/4
• https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim
• http://www.openwall.com/lists/oss-security/2026/05/12/25