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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://code.forgejo.org/forgejo/runner/issues/294
security-advisories@github.com
https://github.com/nektos/act/commit/c28c27e141e8b54f9853de82f421ee09846751f7
security-advisories@github.com
https://github.com/nektos/act/releases/tag/v0.2.86
security-advisories@github.com
https://github.com/nektos/act/security/advisories/GHSA-x34h-54cw-9825
security-advisories@github.com