# CVE-2026-101015: Trusted Domain Project OpenDMARC policy.c improper validation of unsafe equivalence in input

> Remote attackers can exploit improper input validation in OpenDMARC's domain handler to bypass security checks, requiring immediate attention from mail server administrators.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Sep 2026
- **Updated:** 1 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-101015, GHSA-h669-gmgf-xwjw, UBUNTU-CVE-2026-101015

## What is CVE-2026-101015?

CVE-2026-101015 is a medium-severity vulnerability in Trusted Domain Project OpenDMARC, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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 about this disclosure but did not respond in any way.

Weakness: CWE-20 (Improper Input Validation), CWE-1289 (Improper Validation of Unsafe Equivalence in Input)

## Which versions are affected by CVE-2026-101015?


## How do I fix CVE-2026-101015?

No fix has been published for CVE-2026-101015 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101015 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101015 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101015 and fix it if it is affected.

What it is: CVE-2026-101015 is a medium-severity vulnerability in Trusted Domain Project OpenDMARC, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101015 exists.

Affected product: Trusted Domain Project OpenDMARC. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-101015/ (Markdown: https://insights.sbomify.com/CVE-2026-101015/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101015
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101015
- OSV: https://osv.dev/vulnerability/CVE-2026-101015

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101015/
Summaries are generated and may contain mistakes; the official description above is the record.