GHSA-mwjc-5j4x-r686 AVideo has an unauthenticated decrypt oracle leaking any ciphertext

• Packagist wwbn/avideo: <= 26.0 (no fix yet)

Summary The API plugin exposes a `decryptString` action without any authentication. Anyone can submit ciphertext and receive plaintext. Ciphertext is issued publicly (e.g., `view/url2Embed.json.php`), so any user can recover protected tokens/metadata. Severity: High. Details • Entry: `plugin/API/get.json.php` is unauthenticated. • Handler: `plugin/API/API.php` `get_api_decryptString()` (lines ~5945–5966): ```php $string = decryptString($_REQUEST['string']); return new ApiObject($string, empty($string)); ``` No APISecret or user check occurs before decrypting. • Public ciphertext source: `view/url2Embed.json.php` returns `playLink`/`playEmbedLink` (`encryptString(json_encode(...))`) to any caller. PoC 1. Obtain ciphertext: ``` GET /view/url2Embed.json.php?url=https://example.com/video.mp4 ``` Copy `playLink`. 2. Decrypt without auth: ``` POST /plugin/API/get.json.php?APIName=decryptString Content-Type: application/x-www-form-urlencoded string= ``` Response contains the plaintext JSON (videoLink, title, users_id, etc.). Impact • Any encrypted payload produced by the platform can be decrypted by anyone. • Leaks tokens/links intended to be confidential; enables replay and tampering where secrecy was assumed. Mitigation • Require API secret or authenticated/authorized user for `decryptString`, or remove the endpoint. • Prefer one-way signatures (HMAC) instead of exposing generic decryption. • Rotate encryption keys/salts after patch to invalidate exposed ciphertexts.