TI-2026-26367 Aliases CVE-2026-34042 GHSA-x34h-54cw-9825

act: actions/cache server allows malicious cache injection

LOW 36CWE-862Published 2026-03-31 · Updated 2026-03-31

Key facts

Attack vector: Network
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: High · Low · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-862.

Summary

act is a project which allows for local running of github actions. Prior to version 0.2.86, act's built in actions/cache server listens to connections on all interfaces and allows anyone who can connect to it including someone anywhere on the internet to create caches with arbitrary keys and retrieve all existing caches. If they can predict which cache keys will be used by local actions, they can create malicious caches containing whatever files they please most likely allowing arbitrary remote code execution within the docker container. This issue has been patched in version 0.2.86.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00467 40th percentileScored 2026-11-07

Fix Fixed act (nektos): 0.2.86github.com/nektos/act (Go): 0.2.86

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

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

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
nektos	act	before 0.2.86	0.2.86	Patch available	CNA
—	github.com/nektos/act (Go)	before 0.2.86	0.2.86	Patch available	GHSA-x34h-54cw-9825

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-x34h-54cw-9825

Remediation

Fix · CNA act (nektos) Fixed in 0.2.86
Fix · GHSA-x34h-54cw-9825 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

2026-10-02 Threatist record created from CVE-2026-34042
2026-10-03 Alias added: GHSA-x34h-54cw-9825

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-34042

Other 5

TI-2026-26366 act: Unrestricted set-env and add-path command processing enables environment injection CVSS 4.0HIGH 7.7
TI-2023-08900 Unrestricted file upload leading to privilege escalation in act CVSS 3.1HIGH 8.8
TI-2026-53683 act 0.2.81 through 0.2.89 Missing Authorization in the Artifacts V4 Backend CVSS 4.0HIGH 8.7

Sources

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