Gitea: Permanent Fork PR Workflow Approval Gate Bypass
| Field | Value |
|-------|-------|
| Identifier (researcher-assigned) | GITEA-2026-004 |
| Product | Gitea (self-hosted Git service) |
| Component | Gitea Actions — fork pull request approval gate |
| Affected versions | All Gitea releases v1.20.0 and later, including the latest main (1.27.0+dev-289-gb7e95cc48c). The buggy logic was introduced in commit edf98a2dc3 — *"Require approval to run actions for fork pull request (#22803)"*, 2023-02-24 — and has shipped unchanged since. |
| Fixed in | not yet (this disclosure) |
| Authentication required | Yes — one unprivileged Gitea account capable of forking the target repository (the default ability for every authenticated user) |
| User interaction required | Exactly once — a repository administrator must approve a single benign fork PR's workflow run from the attacker. After that, *no further interaction is ever required* for any future fork PR from the same attacker on the same repository. |
| Discovered by | Prakhar Porwal — [email protected] |
| Live-verified on | Gitea main at commit b7e95cc48cc0e0d6fe24c89bb83da5b84a74490f, 2026-05-24 |
1. Executive summary
Gitea Actions enforces an approval gate on workflow runs triggered by fork pull requests, so that an untrusted contributor cannot execute arbitrary workflow YAML on the maintainer's runner infrastructure without explicit consent. The gate is implemented by ifNeedApproval() in services/actions/notifier_helper.go. Its final clause skips the gate whenever the triggering user has any previously-approved run in the same repository:
```go
// services/actions/notifier_helper.go:423-433
if count, err := db.Count[actions_model.ActionRun](ctx, actions_model.FindRunOptions{
RepoID: repo.ID,
TriggerUserID: user.ID,
Approved: true,
}); err != nil {
return false, fmt.Errorf("CountRuns: %w", err)
} else if count > 0 {
log.Trace("do not need approval because user %d has been approved before", user.ID)
return false, nil
}
```
The check is scoped to (repo_id, trigger_user_id) only. It does not consider the pull request, the head commit, the workflow file contents, or any time window. The single approval click on a contributor's *first* fork PR is therefore interpreted by Gitea as *"this user is permanently trusted to execute any workflow YAML on this repository's CI infrastructure forever"* — for every future PR, on any branch, against any commit, regardless of what the workflow does.
This is a structural deviation from the documented intent — the in-source comment on the bypassing path reads *"if it's the first time user … triggered actions"*, implying a per-action-trigger check that the code does not actually perform. It is also a deviation from the equivalent behavior on the platform Gitea Actions is modeled after (GitHub Actions), where the first-contributor gate persists until a PR is merged, not merely approved-to-run.
I have live-reproduced the bypass end-to-end against a current main build. With zero further interaction from the maintainer after the one-time approval, an attacker's second PR's workflow:
- Was created with
need_approval = 0 and approved_by = 0 in the action_run table (i.e. nobody ever approved it, and yet it was not gated). - Was dispatched to the runner immediately.
- Executed arbitrary shell on the runner, with outbound network access, a populated
GITHUB_TOKEN, and access to the cloned source.
Full receipts are in §3.
2. Affected code
Primary
services/actions/notifier_helper.go:401-438 — the ifNeedApproval function:
```go
func ifNeedApproval(ctx context.Context, run *actions_model.ActionRun,
repo *repo_model.Repository, user *user_model.User) (bool, error) {
// 1. don't need approval if it's not a fork PR
// 2. don't need approval if the event is pull_request_target since the
// workflow will run in the context of base branch
if !run.IsForkPullRequest ||
run.TriggerEvent == actions_module.GithubEventPullRequestTarget {
return false, nil
}
// always need approval if the user is restricted
if user.IsRestricted {
return true, nil
}
// don't need approval if the user can write
if perm, err := access_model.GetDoerRepoPermission(ctx, repo, user); err != nil {
return false, fmt.Errorf("GetDoerRepoPermission: %w", err)
} else if perm.CanWrite(unit_model.TypeActions) {
return false, nil
}
// ===== VULNERABLE BLOCK ==================================================
// don't need approval if the user has been approved before
if count, err := db.Count[actions_model.ActionRun](ctx, actions_model.FindRunOptions{
RepoID: repo.ID,
TriggerUserID: user.ID,
Approved: true,
}); err != nil {
return false, fmt.Errorf("CountRuns:
