CVE-2026-45185: Exim

Critical severity, CVSS 9.8. EPSS: 0.9% chance of exploitation in the next 30 days.

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.

Affected products

• Exim Exim: from 4.97, before 4.99.3 (fixed in 4.99.3)

Published 2026-05-12. Last modified 2026-06-17.