Theluckystrike

A blind Server-Side Request Forgery (SSRF) exists when the `[oauth2 client] UPDATE AVATAR = true` setting is enabled. The issue occurs because the server fetches the avatar URL provided by an OAuth2/OIDC provider—typically the `picture` claim—using the default Go HTTP client without applying outbound host or IP restrictions. A low-privileged user who can influence their own `picture` claim can force the Gitea server to make arbitrary outbound HTTP GET requests to loopback addresses, RFC 1918 private network addresses, and IPv4 link-local addresses such as `169.254.169.254`. Technical details include: - **Vulnerable Function**: `oauth2UpdateAvatarIfNeed()` in `routers/web/auth/oauth.go` and `oauth2SignInSync()` in `routers/web/auth/oauth signin sync.go`. - **Vulnerable Variable**: `gothUser.AvatarURL`. While the issue is primarily blind because non-image responses are rejected, the impact increases if the server can reach cloud metadata services or internal services that return valid image data, which could then be stored as the user's avatar.

The `ToHook()` function in `services/webhook/general.go` decrypts the `HeaderAuthorizationEncrypted` field and returns the plaintext authorization header in the API response. This allows repository administrators to read sensitive credentials, such as Bearer tokens, Basic auth credentials, and API keys, set by other administrators. The issue occurs because the function decrypts the secret stored in the database using the server's `SecretKey` before serializing it into the response, effectively converting a write-only secret into a readable credential.

Three code paths bypass the existing Server-Side Request Forgery (SSRF) protections by using raw `http.Get()` instead of the validated `hostmatcher.NewDialContext()` dialer. This allows an attacker to make requests to internal services, scan internal networks (such as `127.0.0.1`, `10.x`, `172.16-31.x`, and `192.168.x`), and steal cloud metadata from endpoints like `169.254.169.254` (e.g., AWS IMDSv1 credentials or GCP tokens). Additionally, the use of the `file://` scheme in the `Open()` function enables local file read, potentially exposing sensitive files such as `/etc/gitea/app.ini` which may contain database credentials and JWT signing secrets. The issue affects the following components: - The `Open()` function in `modules/uri/uri.go`. - Release asset and PR patch downloads in `services/migrations/gitea uploader.go` and `services/migrations/dump.go`. - The `oauth2UpdateAvatarIfNeed()` function in `routers/web/auth/oauth.go`.