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CVE-2026-123369

compose-lint: Compose file text can issue GitHub Actions workflow commands through the compose-lint Action

Products / packages tmatens compose-lint · tmatens/compose-lint · compose-lint

Published

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Severity and exploitation

Not in CISA KEVSource: MODERATE

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 23:05:32 UTC
GitHub_M · CVSS:4.0 · 5.3
Assessment vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
OSV · CVSS:3.1 · 4.3
Assessment vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
OSV · CVSS:4.0 · 5.3
Assessment vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
The headline uses the highest imported catalog score. Assessments can differ by source and CVSS version.

Severity

medium5.3

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Package fixes recorded

Fix versions are recorded for 2 of 2 mapped packages. Check each release branch and any separate product guidance.

What this means

Compose-lint versions before 0.31.0 are affected by a vulnerability that allows a Compose file to issue GitHub Actions workflow commands, potentially creating fake error or warning annotations or hiding log lines. The exit code and pass/fail result are not affected.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

tmatens · GitHub_M

compose-lint

1 range
GitHub_M version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

< 0.31.0

unaffected

unknown

Other versions: unknown

Packages

Compare each installed version with the publisher’s affected ranges. Where a fix is recorded, choose the appropriate release branch and test compatibility before upgrading.

tmatens/compose-lint GitHub Actions
Affected range Recorded fix
From 0.2.0 before 0.31.0Ecosystem versions0.31.0
From 60c091c7cc8f86c6b0c5954031097364fea0a201 before a6a7a76736de1c72abfa96c41ff8af556ffdc55fGit commitsa6a7a76736de1c72abfa96c41ff8af556ffdc55f

Version evidence: OSV · GHSA-6f4g-xm8v-pgv6

View original version evidence (44 explicit versions)
compose-lint PyPI
Affected range Recorded fix
Earlier releases before 0.31.0Ecosystem versions0.31.0

Version evidence: OSV · GHSA-6f4g-xm8v-pgv6

View original version evidence (44 explicit versions)

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

Use the recorded fix for your release branch. Review the publisher’s instructions and test compatibility before upgrading.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

Impact

The GitHub Actions runner treats certain text in a step's output as commands. The legacy form, ##[command], is recognized anywhere in a line. compose-lint's text report prints service names, environment keys and lines of the Compose file, and it does not neutralize ##[. Inside the compose-lint Action, a Compose file from a pull request can therefore:

  • create fake error or warning annotations on the pull request (##[error], ##[warning])
  • fold the rest of the log, including the real verdict, out of sight (##[group])
  • blank out chosen strings for the rest of the log (##[add-mask])

GitHub has postponed removing the deprecated set-output log command, so the runner still honors it. A test run of the Action on a GitHub-hosted runner confirmed that a ::set-output line from a Compose file is processed. Whether it can override the Action's own sarif-written output, which decides whether the SARIF upload step runs, has not been tested.

The exit code and the pass/fail result are not affected. Azure Pipelines parses the same ##[ syntax, so the pip package is listed for anyone printing the text report in other CI systems.

Found during an internal pre-1.0 security review.

Patches

Fixed in 0.31.0. The Action stops the runner from processing workflow commands while compose-lint's output is printed, using a random stop-commands token. The text report also escapes ##[, and :: at the start of a line, in anything taken from the Compose file.

Workarounds

  • In your own workflow, wrap the compose-lint step in ::stop-commands::<random token> and ::<random token>::.
  • Use --format json or --format sarif rather than the text report when linting untrusted pull requests.

Reproduction

services:
  web:
    image: "nginx:1.25"
    environment:
      "##[error]DB_PASSWORD": placeholder
  "##[group]svc":
    image: "nginx:1.25"
    privileged: true

Run through the Action, this produces a fake error annotation and folds the remaining log lines, including the FAIL verdict, into a collapsed group.

References

6 sources
tmatens/compose-lint · security/advisories/GHSA-6f4g-xm8v-pgv6
Security advisoryGitHub_M
tmatens/compose-lint · pull request #918
PatchGitHub_M
tmatens/compose-lint · commit 672bd11
PatchGitHub_M
tmatens/compose-lint · releases/tag/v0.31.0
Release notesGitHub_M
nvd.nist.gov/vuln/detail/CVE-2026-123369
Security advisory
tmatens/compose-lint · repository
Source reference

Inside the record

Evidence available

Package identity
Version evidence
Remediation guidance · not supplied
Weakness classification
Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-123369

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-117 ↗

CWE-117: Improper Output Neutralization for Logs

GitHub_M

Related →
CWE-150 ↗

CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences

GitHub_M

Related →
Contributing organizations · 2
GitHub_M

Assigning organization

2026-11-09
CISA-ADP

Additional data publisher

2026-11-09

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes
  1. CVE · CVE-2026-123369

    Observed 2026-11-09T23:01:04.647Z · upstream updated 2026-11-09T22:55:25.407Z

    Prioritization updated

    before

    []

    after

    [
  {
    "source": "CISA-ADP",
    "type": "SSVC",
    "role": "CISA Coordinator",
    "timestamp": "2026-11-09T22:52:06.368275Z",
    "decisions": [
      {
        "name": "Exploitation",
        "value": "none"
      },
      {
        "name": "Automatable",
        "value": "no"
      },
      {
        "name": "Technical Impact",
        "value": "partial"
      }
    ]
  }
]

Large field values are marked as truncated previews. Original source snapshots remain retained.

Showing up to 50 most recent observed changes.