CVE-2026-123368 compose-lint: .env read through a symlink outside the project can expose the CI job's environment
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-123368?
CVE-2026-123368 is a low-severity vulnerability in tmatens compose-lint, published on 9 Nov 2026.
Official description
compose-lint is a Docker Compose security linter that identifies dangerous misconfigurations before deployment. From 0.22.0 until 0.31.0, compose-lint follows a sibling .env symbolic link outside the project without applying its normal containment check. From 0.28.0, the same gap also affects an include project_directory link outside the project. A pull request can reference a variable from the linked file, causing substitution to place runner file or process-environment data into finding messages written to logs, JSON, SARIF artifacts, and Code Scanning alerts. Reading /proc/self/environ can expose the remainder of the linter process environment because NUL-separated entries are treated as one value, although disclosure requires a workflow that processes untrusted changes with useful environment data and GitHub normally withholds secrets from fork pull requests. The pass or fail result is not changed. This issue is fixed in version 0.31.0.
Which versions are affected by CVE-2026-123368?
2 open source packages ship an affected version, including tmatens/compose-lint and compose-lint.
| Package | Affected | Fixed in |
|---|---|---|
tmatens/compose-lint GitHub Actions | From 0.22.0 | 0.31.0 |
compose-lint PyPI | From 0.22.0 | 0.31.0 |
How do I fix CVE-2026-123368?
Upgrade tmatens/compose-lint to 0.31.0 or later.
Is CVE-2026-123368 being exploited?
There is no known exploitation of CVE-2026-123368 in the wild and no public exploit code.
Sources
Also known as GHSA-6wcv-rj3c-mhv3.