CVE-2026-34042: high-severity vulnerability in nektos act
act: actions/cache server allows malicious cache injection
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.2epss 0.5%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Affected products
nektos · actRelated CVEs — nektos act
In the same product, most dangerous first.
CVE-2023-22726HIGHUnrestricted file upload leading to privilege escalation in actEPSS 1.3%CVE-2026-34041HIGHact: Unrestricted set-env and add-path command processing enables environment injectionEPSS 0.6%CVE-2026-76847HIGHact 0.2.81 through 0.2.89 Missing Authorization in the Artifacts V4 BackendEPSS 0.4%