Use After Free Affecting exim4 package, versions <4.93-13ubuntu1.12+esm1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UBUNTU2004-EXIM4-16693546
- published29 May 2026
- disclosed12 May 2026
Introduced: 12 May 2026
CVE-2026-45185 (opens in a new tab)How to fix?
Upgrade Ubuntu:20.04 exim4 to version 4.93-13ubuntu1.12+esm1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream exim4 package and not the exim4 package as distributed by Ubuntu.
See How to fix? for Ubuntu:20.04 relevant fixed versions and status.
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.
References
- http://people.ubuntu.com/~ubuntu-security/cve/CVE-2026-45185
- 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