Is there a public exploit for CVE-2026-123369?

No public exploit for CVE-2026-123369 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-123369?

CVE-2026-123369 scores CVSS 5.3 (v4.0), rated medium.

What does CVE-2026-123369 affect?

CVE-2026-123369 affects tmatens/compose-lint, compose-lint.

5.3 Medium

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

CVE-2026-123369

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…

Assessment

CVSS: 5.3 (v4.0)
Severity: Medium
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 10 November 2026
Last updated: 10 November 2026
Affected: tmatens/compose-lint · compose-lint
Weakness: CWE-117, CWE-150

CVSS 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

At the source

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