CVE-2026-100891 Other in OpenDMARC
An encoding error in OpenDMARC's IDN handler allows remote attackers to trigger issues, though specific impact details are limited.
- 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-2026-100891?
CVE-2026-100891 is a medium-severity vulnerability in Trusted Domain Project OpenDMARC, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability has been found in Trusted Domain Project OpenDMARC up to 1.4.2. Affected by this issue is the function opendmarc_policy_query_dmarc in the library libopendmarc/opendmarc_policy.c of the component Internationalized Domain Name Handler. Such manipulation leads to encoding error. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Weakness: CWE-172
Which versions are affected by CVE-2026-100891?
How do I fix CVE-2026-100891?
No fix has been published for CVE-2026-100891 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-100891 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100891 exists.
Sources
Also known as DEBIAN-CVE-2026-100891, GHSA-h88r-m2wp-c7v2, UBUNTU-CVE-2026-100891.