# CVE-2026-44359: Meshtastic GitHub repo vulnerable to Arbitrary Code Execution via pull_request_target Fork Checkout in CI Workflow

> Attackers can execute arbitrary code and compromise the repository or runners by submitting pull requests that trigger unsafe CI workflows checking out fork code.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Jul 2026
- **Updated:** 24 Jul 2026
- **Also known as:** UBUNTU-CVE-2026-44359

## What is CVE-2026-44359?

CVE-2026-44359 is a critical vulnerability in meshtastic firmware, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Meshtastic is an open source mesh networking solution. Prior to version 2.7.21.1370b23, the Meshtastic GitHub repository's main_matrix.yml workflow is triggered by pull_request_target  and multiple jobs check out the attacker's fork code and execute it with access to repository secrets and elevated GITHUB_TOKEN permissions. No approval gate exists. Pull requests from external users with author_association: "NONE" triggered the CI workflow automatically. The workflow directly executes attacker-controlled files from the fork checkout. This issue could have resulted in supply chain compromise, self-hosted runner compromise, and/or repository takeover for the repo. This issue is separate from GHSA-6mwm-v2vv-pp96, which addressed a command injection via github.head_ref in the setup job of the same workflow. That fix correctly moved to environment variables. However, the more critical fork checkout vulnerability across the check, build, and build-debian-src jobs was not addressed. Version 2.7.21.1370b23 contains a patch for thie issue.

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-829 (Inclusion of Functionality from Untrusted Control Sphere)

## Which versions are affected by CVE-2026-44359?


## How do I fix CVE-2026-44359?

No fix has been published for CVE-2026-44359 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-44359 being exploited?

There is no known exploitation of CVE-2026-44359 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44359 and fix it if it is affected.

What it is: CVE-2026-44359 is a critical vulnerability in meshtastic firmware, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-44359 in the wild and no public exploit code.

Affected product: meshtastic firmware. 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-2026-44359/ (Markdown: https://insights.sbomify.com/CVE-2026-44359/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44359
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44359
- OSV: https://osv.dev/vulnerability/CVE-2026-44359

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44359/
Summaries are generated and may contain mistakes; the official description above is the record.