CVE-2026-100888 Trusted Domain Project OpenDKIM DKIM Signature Header Selection dkim-canon.c dkim_canon_selecthdrs out-of-bounds write
Remote attackers can trigger an out-of-bounds write in OpenDKIM via crafted DKIM headers, potentially leading to code execution or service crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-100888?
CVE-2026-100888 is a medium-severity memory corruption vulnerability in Trusted Domain Project OpenDKIM, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A weakness has been identified in Trusted Domain Project OpenDKIM up to 2.11.0. This affects the function dkim_canon_selecthdrs of the file libopendkim/dkim-canon.c of the component DKIM Signature Header Selection. Executing a manipulation of the argument h can lead to out-of-bounds write. The attack can be executed remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
Which versions are affected by CVE-2026-100888?
How do I fix CVE-2026-100888?
No fix has been published for CVE-2026-100888 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-100888 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100888 exists.
Sources
Also known as DEBIAN-CVE-2026-100888, GHSA-wm7g-7hm5-7hfr, UBUNTU-CVE-2026-100888.