# CVE-2026-101279: Trusted Domain Project OpenDMARC opendmarc_policy.c integer overflow

> Remote attackers can trigger an integer overflow in OpenDMARC's DMARC parser via the pct argument, potentially causing a denial of service.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-101279, GHSA-3h24-2ph8-4r6f, UBUNTU-CVE-2026-101279

## What is CVE-2026-101279?

CVE-2026-101279 is a medium-severity vulnerability in Trusted Domain Project OpenDMARC, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A security vulnerability has been detected in Trusted Domain Project OpenDMARC up to 1.4.2. This impacts an unknown function of the file libopendmarc/opendmarc_policy.c of the component DMARC Parser. The manipulation of the argument pct leads to integer overflow. Remote exploitation of the attack is possible. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-190 (Integer Overflow or Wraparound), CWE-189

## Which versions are affected by CVE-2026-101279?


## How do I fix CVE-2026-101279?

No fix has been published for CVE-2026-101279 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101279 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101279 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101279 and fix it if it is affected.

What it is: CVE-2026-101279 is a medium-severity vulnerability in Trusted Domain Project OpenDMARC, published on 29 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-2026-101279 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-2026-101279/ (Markdown: https://insights.sbomify.com/CVE-2026-101279/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101279
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101279
- OSV: https://osv.dev/vulnerability/CVE-2026-101279

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101279/
Summaries are generated and may contain mistakes; the official description above is the record.