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TI-2026-26366 Aliases CVE-2026-34041GHSA-xmgr-9pqc-h5vw

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

Priority HIGH 75CWE-74Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00643 51st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed act (nektos): 0.2.86github.com/nektos/act (Go): 0.2.86

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nektosactbefore 0.2.860.2.86Patch availableCNA
—github.com/nektos/act (Go)before 0.2.860.2.86Patch availableGHSA-xmgr-9pqc-h5vw
  • act Vendornektos Affected before 0.2.86 Fixed in 0.2.86 Patch available CNA
  • github.com/nektos/act (Go) Vendor— Affected before 0.2.86 Fixed in 0.2.86 Patch available GHSA-xmgr-9pqc-h5vw

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nektos:act:*:*:*:*:*:*:*:*before 0.2.86Vulnerablenektos
  • cpe:2.3:a:nektos:act:*:*:*:*:*:*:*:* Versions before 0.2.86 Vulnerable ·nektos

Remediation

  • Fix · CNA act (nektos) Fixed in 0.2.86
  • Fix · GHSA-xmgr-9pqc-h5vw github.com/nektos/act (Go) Fixed in 0.2.86 Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-34041
  2. 2026-10-03 Alias added: GHSA-xmgr-9pqc-h5vw
  3. 2026-10-25 EPSS moved to the below the 50th percentile
  4. 2026-10-28 EPSS moved to the 50th–90th percentile

References

Exploit 1

Patch 1

Advisory 2

Other 2

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences