# CVE-2026-101280: Trusted Domain Project OpenDMARC authentication bypass in Multi-Record Set Handler

Source: https://junglewise.ai/threats/cve-2026-101280-a-vulnerability-was-detected-in-trusted-domain-project-opendmarc  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-29. Updated: 2026-09-29  
License: CC BY 4.0 with a link back

CVE-2026-101280 · Severity: high · CVSS 7.3 · Published 2026-09-29

OpenDMARC is a mail authentication system that validates email sender identity to prevent spoofing. A vulnerability in how it processes DMARC policy records allows remote attackers to bypass authentication and spoof emails without detection. The exploit is publicly available and unpatched, leaving OpenDMARC deployments vulnerable to email forgery attacks.

Technologies: [Trusted Domain Project OpenDMARC](https://junglewise.ai/threats/technologies/opendmarc). Vendors: [Trusted Domain Project](https://junglewise.ai/threats/vendors/trusted-domain-project).

## Quick answers

**Is CVE-2026-101280 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-101280 being exploited in the wild.

**How severe is CVE-2026-101280?** High severity, with a CVSS score of 7.3, published 29 September 2026.

**Which products and versions are affected?** Trusted Domain Project OpenDMARC up to 1.4.2.

**Is there a fix for CVE-2026-101280?** 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-2026-101280 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-101280?** 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

The vulnerability exists in the opendmarc_policy_query_dmarc function within the Multi-Record Set Handler component, allowing attackers to manipulate DMARC policy queries and achieve authentication bypass through spoofing. The flaw is remotely exploitable with no authentication or user interaction required. The vendor has not provided a patch despite early notification of the issue.

## Affected products

- Trusted Domain Project OpenDMARC up to 1.4.2

## Timeline

- 2026-09-29: disclosed: Public exploit available
- 2026-09-29: other: Vendor contacted but did not respond

## References

- [https://vuldb.com/cve/CVE-2026-101280](https://vuldb.com/cve/CVE-2026-101280)
- [https://vuldb.com/submit/918282](https://vuldb.com/submit/918282)

## Related threats

- [OpenDMARC improper authentication in SPF macro handler](https://junglewise.ai/threats/cve-2026-101281-a-flaw-has-been-found-in-trusted-domain-project-opendmarc-up-to)
- [Trusted Domain Project OpenDMARC integer overflow in DMARC parser](https://junglewise.ai/threats/cve-2026-101279-a-security-vulnerability-has-been-detected-in-trusted-domain)
- [Trusted Domain Project OpenDMARC origin validation error in PSL Wildcard Handler](https://junglewise.ai/threats/cve-2026-101278-a-weakness-has-been-identified-in-trusted-domain-project)
- [Trusted Domain Project OpenDMARC exception handling in strcasecmp](https://junglewise.ai/threats/cve-2026-101017-a-vulnerability-was-found-in-trusted-domain-project-opendmarc-up)
- [Trusted Domain Project OpenDMARC exception handling in DMARC policy parsing](https://junglewise.ai/threats/cve-2026-101016-a-vulnerability-has-been-found-in-trusted-domain-project)