Is CVE-2026-100888 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100888 being exploited in the wild.

How severe is CVE-2026-100888?

High severity, with a CVSS score of 7.3, published 28 September 2026.

Which products and versions are affected?

Trusted Domain Project OpenDKIM up to 2.11.0.

Is there a fix for CVE-2026-100888?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-100888 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-100888?

Check whether you run Trusted Domain Project OpenDKIM at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-100888: Trusted Domain Project OpenDKIM out-of-bounds write in header selection

CVE-2026-100888 · Severity: high · CVSS 7.3 · Published 2026-09-28

OpenDKIM is a cryptographic authentication mechanism for email messages that verifies sender identity. A flaw in the header selection function allows remote attackers to write data beyond allocated memory boundaries by manipulating header parameters, potentially leading to service crashes or code execution. Exploit code is publicly available and the vendor has not issued a response or patch.

Technologies: Trusted Domain Project OpenDKIM. Vendors: Trusted Domain Project.

Quick answers

Is CVE-2026-100888 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100888 being exploited in the wild.
How severe is CVE-2026-100888?: High severity, with a CVSS score of 7.3, published 28 September 2026.
Which products and versions are affected?: Trusted Domain Project OpenDKIM up to 2.11.0.
Is there a fix for CVE-2026-100888?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-100888 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-100888?: Check whether you run Trusted Domain Project OpenDKIM at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An out-of-bounds write vulnerability exists in the dkim_canon_selecthdrs function within libopendkim/dkim-canon.c, triggered by manipulation of the 'h' argument during DKIM signature header selection. The vulnerability is remotely exploitable without authentication requirements and allows memory corruption that could lead to denial of service or arbitrary code execution. No patch from the vendor has been released.

Affected products

Trusted Domain Project OpenDKIM up to 2.11.0

Timeline

2026-09-28: disclosed
other: Exploit code made public

References

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