CVE-2026-125121 compose-lint: Text in a pull request can still issue CI workflow commands through compose-lint 0.31.0's output
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-125121?
CVE-2026-125121 is a medium-severity vulnerability in tmatens compose-lint, published on 10 Nov 2026.
Official description
compose-lint is a Docker Compose security linter that identifies dangerous misconfigurations before deployment. In version 0.31.0, compose-lint escapes GitHub Actions workflow-command openers only after ASCII spaces and tabs, while the runner strips all leading Unicode whitespace before interpreting a line. Untrusted Compose values or repository paths beginning with Unicode whitespace followed by :: can therefore reach the text report, fix guidance, the fix dry-run diff, and stderr diagnostics as workflow commands when the package, pre-commit hook, or Docker image runs directly in CI. The GitHub Action is not affected because it disables command processing, and the flaw does not change the lint pass or fail result. This issue is fixed in version 0.32.0.
Which versions are affected by CVE-2026-125121?
1 open source package ship an affected version, including compose-lint.
| Package | Affected | Fixed in |
|---|---|---|
compose-lint PyPI | From 0.31.0 | 0.32.0 |
How do I fix CVE-2026-125121?
Upgrade compose-lint to 0.32.0 or later.
Is CVE-2026-125121 being exploited?
There is no known exploitation of CVE-2026-125121 in the wild and no public exploit code.
Sources
Also known as GHSA-r7j4-crjv-h467.