CVE-2025-53637
📋 TL;DR
This CVE describes a command injection vulnerability in Meshtastic's GitHub Actions workflow that allows attackers to execute arbitrary code in the CI/CD pipeline. Attackers who fork the repository and create pull requests can exploit this to inject unauthorized code. This affects organizations using Meshtastic firmware versions before 2.6.6.
💻 Affected Systems
- Meshtastic Firmware
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the CI/CD pipeline leading to supply chain attack, malicious code injection into production builds, and potential backdoor insertion into distributed firmware.
Likely Case
Unauthorized code execution in GitHub Actions runners, potential repository contamination, and disruption of build processes.
If Mitigated
Limited impact with proper pull request review processes and restricted GitHub Actions permissions.
🎯 Exploit Status
Exploitation requires GitHub account and ability to fork/create pull requests against the repository.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.6.6
Vendor Advisory: https://github.com/meshtastic/firmware/security/advisories/GHSA-6mwm-v2vv-pp96
Restart Required: No
Instructions:
1. Update Meshtastic firmware to version 2.6.6 or later. 2. Verify the .github/workflows/main_matrix.yml file has been updated to safely handle user input.
🔧 Temporary Workarounds
Disable pull_request_target workflow
allTemporarily disable the vulnerable GitHub Actions workflow until patching is complete.
Navigate to repository Settings > Actions > Workflow permissions > Disable workflow
Restrict GitHub Actions permissions
allLimit GitHub Actions to read-only permissions for pull requests from forks.
Set workflow permissions to 'Read repository contents permission' for pull requests
🧯 If You Can't Patch
- Implement mandatory code review for all pull requests, especially from external contributors
- Monitor GitHub Actions logs for suspicious activity and unauthorized code execution attempts
🔍 How to Verify
Check if Vulnerable:
Check if .github/workflows/main_matrix.yml contains unsafe shell command interpolation at lines 34-41 in versions before 2.6.6Check Version:
Check Meshtastic firmware version in device settings or build configurationVerify Fix Applied:
Verify the main_matrix.yml file has been updated to safely handle shell command execution and user input📡 Detection & Monitoring
Log Indicators:
- Unauthorized shell commands in GitHub Actions logs
- Unexpected code execution in CI/CD pipeline
- Suspicious pull request activity from forks
Network Indicators:
- Unusual outbound connections from GitHub Actions runners
SIEM Query:
source="github_actions" AND (command_injection OR shell_execution)