CVE Alert: CVE-2026-101015 – Trusted Domain Project

A flaw has been found in Trusted Domain Project OpenDMARC up to 1.4.2. Affected by this issue is some unknown functionality of the file policy.c of the component Domain Handler. Executing a manipulation can lead to improper validation of unsafe equivalence in input. The attack may be launched remotely. The exploit has been published and may be used. The vendor was contacted early this disclosure but did not respond in any way.

**Risk verdict:** Treat this as an elevated exposure for internet-reachable DMARC policy services: a public exploit is reported, but KEV, SSVC and EPSS status are not provided, so active exploitation and relative prevalence remain unconfirmed.

**Why this matters:** If exploitable in your deployment, altered policy handling could weaken email-authentication decisions, enabling targeted spoofing or disruption of mail flows. The precise security outcome is unclear because the report does not explain the affected input or exploit conditions; validate impact against your configuration.

**Most likely attack path:** The stated metrics indicate a network-reachable attack requiring no prior privileges, user action or special conditions, which makes exposed services plausible targets. Scope is unchanged, so direct impact appears limited to the vulnerable service’s own security authority; downstream risk depends on how mail gateways consume its policy decisions.

**Who is most exposed:** Prioritise organisations running the affected DMARC service on public-facing mail infrastructure, especially where it informs gateway acceptance or quarantine decisions.

Review DMARC service logs for malformed or unusual policy inputs and parsing errors.

Compare policy evaluation results with DNS records and expected enforcement outcomes.

Monitor for anomalous authentication decisions, spoofing reports and unexpected mail-flow changes.

Preserve relevant logs and check for unexplained configuration or process changes.

Mitigation and prioritisation:

Identify affected deployments and obtain vendor or maintainer guidance on a fixed release; no remediation version is established in the supplied data.

Restrict network access to trusted mail infrastructure where feasible.

Add independent policy validation or conservative gateway handling as a compensating control.

Test changes in staging, then deploy promptly with rollback and mail-flow monitoring; reassess urgency when exploitation-status data becomes available.

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