Environment Variable Injection in GitHub Actions
Impact
The @actions/core npm module addPath and exportVariable functions communicate with the Actions Runner over stdout by generating a string in a specific format. Workflows that log untrusted data to stdout may invoke these commands, resulting in the path or environment variables being modified without the intention of the workflow or action author.
Patches
The runner will release an update that disables the set-env and add-path workflow commands in the near future. For now, users should upgrade to @actions/core v1.2.6 or later, and replace any instance of the set-env or add-path commands in their workflows with the new Environment File Syntax. Workflows and actions using the old commands or older versions of the toolkit will start to warn, then error out during workflow execution.
Workarounds
None, it is strongly suggested that you upgrade as soon as possible.
For more information
If you have any questions or comments about this advisory:
- Open an issue in Actions Toolkit
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | @actions/core | < 1.2.6 | 1.2.6 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N- Weakness (CWE)
CWE-20, CWE-77- Platform
- npm
- Package
@actions/core- Disclosed
- 01.10.2020
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-mfwh-5m23-j46w - CC BY 4.0
Vulnerability history: @actions/core
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 10.2020 08.2022
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 1
- Low 1
Disclosures per year
- 2020: 1
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 0
-
Environment Variable Injection in GitHub Actions this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.