What’s Vulnerable › Vulnerabilities

CVE-2026-34041: act: Unrestricted set-env and add-path command processing enables environment injection

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-31 · updated 2026-06-17
• Weakness: CWE-74

Description

act is a project which allows for local running of github actions. Prior to version 0.2.86, act unconditionally processes the deprecated ::set-env:: and ::add-path:: workflow commands, which was disabled due to environment injection risks. When a workflow step echoes untrusted data to stdout, an attacker can inject these commands to set arbitrary environment variables or modify the PATH for all subsequent steps in the job. This issue has been patched in version 0.2.86.

Affected products

• nektos act: before 0.2.86 — fixed in 0.2.86

How to fix

Upgrade to a fixed version: nektos act 0.2.86. Check the vendor advisory for mitigations.

References

• https://github.com/nektos/act/commit/0c739c8e39c41aa5a07665f732da9cab6df0097a
• https://github.com/nektos/act/releases/tag/v0.2.86
• https://github.com/nektos/act/security/advisories/GHSA-xmgr-9pqc-h5vw

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