Threat Intelligence / CVE / CVE-2026-45185
CVE-2026-45185
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 v3 vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses (CWE)
CWE-416
Threats tracking this CVE
- Dead.Letter — CVE-2026-45185 Unauthenticated Pre-Auth RCE in Exim via Use-After-Free in BDAT/GnuTLS — CRITICAL
References
- https://exim.org/
- https://code.exim.org/exim/wiki/wiki/EximSecurity
- https://exim.org/static/doc/security/CVE-2026-45185.txt
- https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-exim
- https://news.ycombinator.com/item?id=48111748
- https://www.openwall.com/lists/oss-security/2026/05/12/4
- https://exim.org/static/doc/security/EXIM-Security-2026-05-01.1/
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