CVE-2026-100891: A vulnerability has been found in Trusted Domain Project OpenDMARC up to 1.4.2
CVE-2026-100891 analysis covering impact, affected products, versions, remediation, and cross-checked defender guidance.
CVE-2026-100891 is a vulnerability published by NVD on 9/28/2026.
What happened
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.
Affected products and versions
- NVD has not published a normalized affected-product configuration yet.
Severity and weakness
CVSS: HIGH 7.3. Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
Weaknesses: CWE-172.
Known exploitation
No CISA KEV entry is currently attached to the NVD record.
What defenders should do
- Identify whether the affected product and version range exists in production.
- Review vendor advisories and release notes before change windows.
- Patch, upgrade, disable the vulnerable component, or apply vendor mitigations.
- Verify the running version after deployment, not only the package inventory.
Official and supporting references
- No vendor advisory tagged by NVD at draft time.