A user who can open a fork pull request can place workflow content with a shared run-level concurrency group into a Gitea Actions run that is awaiting approval. When a later run in that group cancels the blocked job, the run becomes terminal while still marked as needing approval. If a maintainer later approves the run, Gitea passed the already-cancelled job back through concurrency preparation, set it to waiting, and made it claimable by a matching runner, executing fork-controlled workflow code. Exploitation requires the maintainers later approval action, Actions to be enabled, and a runner that accepts the repositorys jobs.
Weakness
The product supports a session in which more than one behavior must be performed by an actor, but it does not properly ensure that the actor performs the behaviors in the required sequence.
Extended Description
By performing actions in an unexpected order, or by omitting steps, an attacker could manipulate the business logic of the product or cause it to enter an invalid state. In some cases, this can also expose resultant weaknesses. For example, a file-sharing protocol might require that an actor perform separate steps to provide a username, then a password, before being able to transfer files. If the file-sharing server accepts a password command followed by a transfer command, without any username being provided, the product might still perform the transfer. Note that this is different than CWE-696, which focuses on when the product performs actions in the wrong sequence; this entry is closely related, but it is focused on ensuring that the actor performs actions in the correct sequence. Workflow-related behaviors include: