CVE-2026-100888
CVE-2026-100888
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.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Weakness classification (CWE)
References
- vuldb.com/vuln/410837 (technical-description, vdb-entry)
- vuldb.com/vuln/410837/cti (signature, permissions-required)
- vuldb.com/cve/CVE-2026-100888 (third-party-advisory)
- vuldb.com/submit/917015 (third-party-advisory)
- weitongli.com/share/opendkim-h-tag-oob-write.html (exploit)
Frequently asked questions
- What is CVE-2026-100888?
- CVE-2026-100888 is a high-severity vulnerability, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.3/10. Published 2026-09-28.
- How severe is CVE-2026-100888?
- High severity. CVSS v3 base score is 7.3 out of 10.