by Kastro
Paper/Archive/CVE-2026-34041

CVE-2026-34041

nektos act — act: Unrestricted set-env and add-path command processing enables environment injection

EPSS 0.6%public exploitCVSS 9.8
critical.is priorityof 100
50
CVSS 9.8 (ADP)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 50.8.508 × 2010.2Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
act< 0.2.86–CNA

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub_M (CNA)7.7CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

refgithub.com/nektos/act/security/advisories/GHSA-xmgr-9pqc-h5vwrefgithub.com/nektos/act/commit/0c739c8e39c41aa5a07665f732da9cab6df0097arefgithub.com/nektos/act/releases/tag/v0.2.86