Repository Visibility Manipulation via Git Push Options

Affected: Go: code.gitea.io/gitea

### Repository Visibility Manipulation via Git Push Options

| Field | Value | |-------|-------| | **Affected File** | `routers/private/hook_post_receive.go` | | **Affected Function** | `HookPostReceive()` | | **Affected Lines** | 173–225 | | **Prerequisite** | Attacker must have owner-level or admin collaborator access to the target repository |

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#### Description

Gitea's post-receive git hook handler processes git push options — key-value pairs transmitted by a client during `git push` using the `-o` flag. Two undocumented push options, `repo.private` and `repo.template`, allow any user with repository owner or admin-collaborator access to toggle the visibility (`private/public`) and template status of a repository as a side effect of a normal git push.

This capability was originally intended solely for the "push-to-create" feature (automatically creating a repo on first push). However, the options are processed without restriction on already-existing repositories, and — critically — the visibility change bypasses every control that a proper settings change would trigger:

- No entry written to the repository's audit/activity log - No webhook event fired (`repository` event with `visibility_changed` action) - No org-level notification to owners - No team permission re-calculation - No email alert to watchers - The database update uses `UpdateRepositoryColsNoAutoTime`, which also suppresses the `updated_at` timestamp change

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#### Vulnerable Code

**`routers/priv…