compose-lint: Text in a pull request can still issue CI workflow commands through compose-lint 0.31.0's output
- Exploited
- No known exploitation
- Fix
- Fixed in 0.32.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 0.32.0.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 22/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
compose-lint, a Docker Compose security linter, can be made to print GitHub Actions workflow commands when it runs directly in CI, because it fails to escape Unicode whitespace before a "::" sequence in its output. An attacker can do this remotely, without logging in, by getting untrusted Compose values or repository paths into a scanned file, but a user action is needed for the lint run to happen.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original 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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure7/25Reachable over the network without a login · Unknown: No advisory context yet
- Reach10/20Affects PyPI packages
- Severity5.3/10CVSS 5.3
- No patch0/5No signal
What would change the score
- Would score about 77 if added to CISA KEV
- Would score about 72 if CISA's SSVC rates exploitation active
- Would score about 37 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 0.32.0.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-125121 (compose-lint: Text in a pull request can still issue CI workflow commands through compose-lint 0.31.0's output), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-125121 (entry last updated 2026-11-10): Affected: - tmatens compose-lint: from 0.31.0, fixed in 0.32.0 - PyPI package compose-lint: from 0.31.0, fixed in 0.32.0 Fixed versions: 0.32.0. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-125121 is not listed as of cve.now's last read. This KEV status is for CVE-2026-125121 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Packages (PyPI): find every lockfile in each project and run check_stack from the cve.now MCP server on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies. Verify against the linked advisories before concluding, and cite the date you read each one: - https://github.com/tmatens/compose-lint/security/advisories/GHSA-r7j4-crjv-h467 - https://github.com/tmatens/compose-lint/pull/945 - https://github.com/tmatens/compose-lint/commit/542e63126f795564a65c63887ea0dc558a500688 - https://github.com/advisories/GHSA-6f4g-xm8v-pgv6 - https://github.com/tmatens/compose-lint/releases/tag/v0.32.0 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-125121 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-125121.
Timeline
- CVE published
- Record last updated
- First seen by cve.now
Affected versions
- tmatens compose-lint
From 0.31.0 · fixed in 0.32.0
- compose-lintPyPI
From 0.31.0 · fixed in 0.32.0
Evidence 7
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 4
- Advisory
- Repository
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-125121
Is CVE-2026-125121 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: cve.now feed data
Which versions are affected by CVE-2026-125121?
compose-lint: from 0.31.0 before 0.32.0. compose-lint (PyPI): from 0.31.0 before 0.32.0.Source: cve.now feed data
How do I fix CVE-2026-125121?
Upgrade to a fixed version: 0.32.0.Source: cve.now feed data