# CVE-2026-123368: compose-lint: .env read through a symlink outside the project can expose the CI job's environment


- **Severity:** Low 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`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 9 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-6wcv-rj3c-mhv3

## 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.

Weakness: CWE-59 (Improper Link Resolution Before File Access), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-123368?

2 open source packages ship an affected version, including tmatens/compose-lint and compose-lint.


| Package | Ecosystem | 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123368 and fix it if it is affected.

What it is: CVE-2026-123368 is a low-severity vulnerability in tmatens compose-lint, published on 9 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123368 in the wild and no public exploit code.

Affected packages and fixed versions:
- tmatens/compose-lint (GitHub Actions): affected from 0.22.0; fixed in 0.31.0
- compose-lint (PyPI): affected from 0.22.0; fixed in 0.31.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-123368/ (Markdown: https://insights.sbomify.com/CVE-2026-123368/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123368
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123368
- OSV: https://osv.dev/vulnerability/CVE-2026-123368

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123368/
Summaries are generated and may contain mistakes; the official description above is the record.