buildalon/setup-steamcmd leaked authentication token in job output logs

Exploitation

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

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary Log output includes authentication token that provides full account access Details The post job action prints the contents of config/config.vdf which holds the saved authentication token and can be used to sign in on another machine. This means any public use of this action leaves authentication tokes for the associated steam accounts publicly available. Additionally, userdata/$userid$/config/localconfig.vdf contains potentially sensitive information which should not be included in public logs. PoC Use the following workflow step Impact Anyone who has used this workflow action with a steam account is affected and has had valid authentication tokens leaked in the job logs. This is particularly bad for public repositories, as anyone with a GitHub account can access the logs and view the token.

Published by the source

21 Jul 2025, 19:12 UTC

Last modified by the source

21 Jul 2025, 19:12 UTC

Source last checked

26 Oct 2026, 17:08 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-mj96-mh85-r574

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# Patch Next advisory brief: GHSA-mj96-mh85-r574

Advisory: buildalon/setup-steamcmd leaked authentication token in job output logs
IDs: GHSA-mj96-mh85-r574
Record: https://patchnext.com/advisories/ghsa-mj96-mh85-r574 (revision 1, source checked 26 Oct 2026, 17:08 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: buildalon/setup-steamcmd 1.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- GitHub Actions buildalon/setup-steamcmd: affected < 1.1.0; fixed in 1.1.0

## Suggested inspection (read-only)
- GitHub Actions buildalon/setup-steamcmd: 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 buildalon/setup-steamcmd.
- 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-mj96-mh85-r574 (GitHub-reviewed advisory GHSA-mj96-mh85-r574 lists affected ranges: GitHub Actions buildalon/setup-steamcmd >=0 <1.1.0)

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