Out-of-bounds write in Exim - CVE-2026-94054
Published: September 29, 2026
Vulnerability identifier: #VU152755
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-94054
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause an out-of-bounds heap read and write.
The vulnerability exists due to an out-of-bounds write in Proxy Protocol v1 handling when processing Proxy Protocol v1 data from a configured proxy. A remote attacker can supply Proxy Protocol v1 data through the configured proxy to cause an out-of-bounds heap read and write.
The installation must be built and configured for Proxy-Protocol use, and the configured proxy must be buggy or compromised.
Affected software
Exim
Debian Linux
exim4 (Debian package)
Debian Linux
exim4 (Debian package)
How to mitigate CVE-2026-94054
Install security update from vendor's website.
Exim - update to 4.100.1
exim4 (Debian package) - update to 4.98.2-1+deb13u5
exim4 (Debian package) - update to 4.98.2-1+deb13u5