compose-lint: A committed symlink makes compose-lint quote a file from outside the project into its output

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

2.3 · 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 · score source

EPSS

• CVE-2026-123373: 0.45% estimated exploitation activity in the next 30 days; percentile 39.58 (FIRST EPSS, 2026-11-10). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Like Docker Compose, compose-lint follows symlinks when it reads a project's files. Unlike Compose, compose-lint up to 0.24.0 could then put the contents of a file from *outside* the project into its output, where the author of a pull request can read it. A pull request can commit a symlink, under a name compose-lint reads, pointing at a file on the CI runner: - The Compose file itself (0.2.0–0.24.0). A `compose.yml` that is a symlink, whether the pre-commit hook passes its name or the Action or a bare run finds it. - `compose.override.yml` (0.22.0–0.24.0), which compose-lint merges automatically. - A `COMPOSE_FILE` entry (0.22.0–0.24.0) in a `.env` beside the Compose file. When the target is not valid YAML, the parse error quotes the line it failed on. Docker Compose, given the same file, reports only a line number. That line reaches standard error (the job log), JSON `errors[]`, and the SARIF `toolExecutionNotifications`, which the Action uploads to Code…

Published by the source

10 Nov 2026, 15:57 UTC

Last modified by the source

10 Nov 2026, 16:15 UTC

Source last checked

11 Nov 2026, 07:05 UTC

1. Revision 2 · amended · 11 Nov 2026

   Amended from osv record GHSA-whr6-fgpq-fpv9

2. Revision 1 · created · 10 Nov 2026

   Published from ghsa record GHSA-whr6-fgpq-fpv9

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# Patch Next advisory brief: CVE-2026-123373

Advisory: compose-lint: A committed symlink makes compose-lint quote a file from outside the project into its output
IDs: CVE-2026-123373, GHSA-whr6-fgpq-fpv9
Record: https://patchnext.com/advisories/cve-2026-123373 (revision 2, source checked 11 Nov 2026, 07:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: compose-lint 0.25.0; tmatens/compose-lint 0.25.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI compose-lint: affected >= 0.2.0, < 0.25.0; fixed in 0.25.0
- GitHub Actions tmatens/compose-lint: affected >= 0.2.0, < 0.25.0; fixed in 0.25.0

## Suggested inspection (read-only)
- `python -m pip show compose-lint`: prints the installed version. Run with the environment that serves production active.
- GitHub Actions tmatens/compose-lint: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on compose-lint, tmatens/compose-lint.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-whr6-fgpq-fpv9 (GitHub-reviewed advisory GHSA-whr6-fgpq-fpv9 lists affected ranges: PyPI compose-lint >=0.2.0 =0.2.0 <=0.24.0)
- Verified: https://osv.dev/vulnerability/GHSA-whr6-fgpq-fpv9 (OSV record GHSA-whr6-fgpq-fpv9 lists affected ranges: PyPI compose-lint >=0.2.0 =0.2.0 <0.25.0 (fixed))

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