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HIGH severity

CVE-2026-100889

HIGH

CVE-2026-100889 is a high-severity (CVSS 7.3) CWE-189 vulnerability. No vendor fix is recorded yet; mitigation options are listed below.

A vulnerability was detected in Trusted Domain Project OpenDKIM up to 2.11.0. Affected is the function dkim_qp_decode of the file util.c of the component Decoder. The manipulation results…

Published
Sep 28, 2026
Updated
Sep 28, 2026
Affected
—
Patched
—
Exploits
None indexed
Exploitation data as of Sep 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Description

A vulnerability was detected in Trusted Domain Project OpenDKIM up to 2.11.0. Affected is the function dkim_qp_decode of the file util.c of the component Decoder. The manipulation results in off-by-one. The attack may be performed from remote. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

  2. Remediation status

    No fixed release is recorded for CVE-2026-100889 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

A vulnerability was detected in Trusted Domain Project OpenDKIM up to 2.11.0. Affected is the function dkim_qp_decode of the file util.c of the component Decoder. The manipulation results in off-by-one. The attack may be performed from remote. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
O3 Security · Impact-Aware SCA

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CVE-2026-100889: High 7.3 severity | O3 Security