# CVE-2026-101277: Trusted Domain Project OpenDKIM Tag Tokenizer dkim.c dkim_process_set less trusted source

> Remote attackers can exploit a tag tokenizer flaw in OpenDKIM to use less trusted sources, potentially bypassing signature verification.

- **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:** 28 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-101277, GHSA-frgp-cm59-pw23, UBUNTU-CVE-2026-101277

## What is CVE-2026-101277?

CVE-2026-101277 is a medium-severity vulnerability in Trusted Domain Project OpenDKIM, 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 security flaw has been discovered in Trusted Domain Project OpenDKIM up to 2.11.0. The impacted element is the function dkim_process_set of the file dkim.c of the component Tag Tokenizer. Performing a manipulation results in use of less trusted source. The attack may be initiated remotely. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-348 (Use of Less Trusted Source)

## Which versions are affected by CVE-2026-101277?


## How do I fix CVE-2026-101277?

No fix has been published for CVE-2026-101277 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101277 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101277 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101277 and fix it if it is affected.

What it is: CVE-2026-101277 is a medium-severity vulnerability in Trusted Domain Project OpenDKIM, 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-2026-101277 exists.

Affected product: Trusted Domain Project OpenDKIM. 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-2026-101277/ (Markdown: https://insights.sbomify.com/CVE-2026-101277/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101277
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101277
- OSV: https://osv.dev/vulnerability/CVE-2026-101277

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101277/
Summaries are generated and may contain mistakes; the official description above is the record.