CVE-2026-101280 Details
Description
A vulnerability was detected in Trusted Domain Project OpenDMARC up to 1.4.2. Affected is the function opendmarc_policy_query_dmarc of the component Multi-Record Set Handler. The manipulation results in authentication bypass by spoofing. The attack can be executed remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
An authentication bypass vulnerability has been identified in Trusted Domain Project OpenDMARC versions through 1.4.2. The issue arises in the Multi-Record Set Handler, specifically within the 'opendmarc_policy_query_dmarc' function. This vulnerability allows remote attackers to spoof DMARC records, bypassing authentication checks. OpenDMARC incorrectly processes multiple DMARC records at a single node by applying the first record it retrieves, which can lead to downgrading the DMARC policy from 'reject' to 'none'.
To address this vulnerability, OpenDMARC should be configured to count the number of DMARC records after filtering for the 'v=DMARC1' prefix. If more than one record remains, the set should be discarded, and the domain treated as having no policy, in accordance with RFC 7489 and RFC 9989. Additionally, a diagnostic message should be emitted to alert domain operators of the misconfiguration.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 29, 2026CISA-ADP
Assessed Sep 29, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://vuldb.com/cve/CVE-2026-101280 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/submit/918282 | [email protected] | Issue TrackingPermission Required |
| https://vuldb.com/vuln/411037 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/vuln/411037/cti | [email protected] | Content Wall |
| https://xuyongzhe-vt.github.io/share/opendmarc-multi-record-downgrade.html | [email protected] | ExploitTechnical Analysis |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-287 | Improper Authentication | [email protected] |
| CWE-290 | Authentication Bypass by Spoofing | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Trusted Domain Project OpenDMARC | <= 1.4.2 (semver) ~1.4 ~1.3 |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 29, 2026 | CVE Modified | CISA-ADP |
| Sep 29, 2026 | New CVE Received | [email protected] |