Is CVE-2026-100890 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-100890 being exploited in the wild.

How severe is CVE-2026-100890?

Medium severity, with a CVSS score of 5.3, published 28 September 2026.

Which products and versions are affected?

Trusted Domain Project OpenDMARC up to 1.4.2.

Is there a fix for CVE-2026-100890?

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-2026-100890 attacked?

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

Am I affected by CVE-2026-100890?

Check whether you run Trusted Domain Project OpenDMARC 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-2026-100890: OpenDMARC null pointer dereference in SPF parser

CVE-2026-100890 · Severity: medium · CVSS 5.3 · Published 2026-09-28

OpenDMARC is an open-source email authentication library used to validate DMARC, SPF, and DKIM email signatures. A null pointer dereference vulnerability in the SPF parser allows an attacker to send a malicious email that crashes the mail processing service, causing a denial of service. The vulnerability can be triggered remotely without authentication.

Technologies: Trusted Domain Project OpenDMARC. Vendors: Trusted Domain Project.

Quick answers

Is CVE-2026-100890 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-100890 being exploited in the wild.
How severe is CVE-2026-100890?: Medium severity, with a CVSS score of 5.3, published 28 September 2026.
Which products and versions are affected?: Trusted Domain Project OpenDMARC up to 1.4.2.
Is there a fix for CVE-2026-100890?: 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-2026-100890 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-100890?: Check whether you run Trusted Domain Project OpenDMARC 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

A null pointer dereference exists in the opendmarc_spf_ipv6_explode function in libopendmarc/opendmarc_spf.c when processing SPF records with malformed IPv6 addresses. An attacker can craft an email with a specially formatted SPF record to trigger a null pointer dereference in the affected function, causing the application to crash. This is a remote, unauthenticated attack requiring only the ability to send email or DNS replies.

Affected products

Trusted Domain Project OpenDMARC up to 1.4.2

Timeline

2026-09-28: disclosed

References

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