Nektos Act vulnerabilities

CVE-2026-34041 [CRITICAL] CWE-74 CVE-2026-34041: act is a project which allows for local running of github actions. Prior to version 0.2.86, act unco 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 e

CVE-2023-22726 [HIGH] CWE-434 CVE-2023-22726: act is a project which allows for local running of github actions. The artifact server that stores a act is a project which allows for local running of github actions. The artifact server that stores artifacts from Github Action runs does not sanitize path inputs. This allows an attacker to download and overwrite arbitrary files on the host from a Github Action. This issue may lead to privilege escalation. The /upload endpoint is vulnerable to path t

CVE-2026-34042 [HIGH] CWE-862 CVE-2026-34042: act is a project which allows for local running of github actions. Prior to version 0.2.86, act's bu 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 cach

CVE-2026-76847 [HIGH] CWE-321 CVE-2026-76847: act starts an HTTP Artifacts V4 backend whenever a workflow uses actions/upload-artifact@v4 or actio act starts an HTTP Artifacts V4 backend whenever a workflow uses actions/upload-artifact@v4 or actions/download-artifact@v4. The control-plane RPCs of that backend, including CreateArtifact, GetSignedArtifactURL, ListArtifacts, FinalizeArtifact and DeleteArtifact, accept a caller-supplied workflow_run_backend_id and never check that it belongs to the