GHSA-mj96-mh85-r574 buildalon/setup-steamcmd leaked authentication token in job output logs

Not scored Published 21 Jul 2025

The setup-steamcmd action leaks Steam authentication tokens in public logs, allowing attackers to hijack accounts and access sensitive data.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is GHSA-mj96-mh85-r574?

GHSA-mj96-mh85-r574 is a vulnerability in buildalon/setup-steamcmd, published on 21 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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/$user_id$/config/localconfig.vdf contains potentially sensitive information which should not be included in public logs.

PoC

Use the following workflow step

steps:
      - name: Setup SteamCMD
        uses: buildalon/[email protected]

      - name: Sign into steam
        shell: bash
        run: |
          steamcmd +login ${{ secrets.WORKSHOP_USERNAME }} ${{ secrets.WORKSHOP_PASSWORD }} +quit

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.

Which versions are affected by GHSA-mj96-mh85-r574?

1 open source package ship an affected version, including buildalon/setup-steamcmd.

Package	Affected	Fixed in
`buildalon/setup-steamcmd` GitHub Actions	All versions	`1.1.0`

How do I fix GHSA-mj96-mh85-r574?

Upgrade buildalon/setup-steamcmd to 1.1.0 or later.

Is GHSA-mj96-mh85-r574 being exploited?

There is no known exploitation of GHSA-mj96-mh85-r574 in the wild and no public exploit code.