GHSA-q4x6-6mm2-crg9 WWBN AVideo has a Live restream log callback flow enabling stored SSRF to internal services

• Packagist WWBN/AVideo: <= 26.0 (no fix yet)

Summary The Live restream log callback flow accepted an attacker-controlled `restreamerURL` and later fetched that stored URL server-side, enabling stored SSRF for authenticated streamers. The vulnerable flow allowed a low-privilege user with streaming permission to store an arbitrary callback URL and trigger server-side requests to loopback or internal HTTP services through the restream log feature. Details The vulnerable chain was: 1. `plugin/Live/view/getRestream.json.php` exposed a fresh `tokenForAction` 2. `plugin/Live/view/Live_restreams/verifyTokenForAction.json.php` exchanged it for a valid `responseToken` 3. `plugin/Live/view/Live_restreams_logs/add.json.php` accepted attacker-controlled `restreamerURL` 4. `plugin/Live/view/getRestream.json.php` and `plugin/Live/view/Live_restreams/getAction.json.php` later fetched that stored URL server-side The original issue existed because the `responseToken` was accepted, but the callback destination was not tightly constrained to trusted restreamer endpoints. The maintainer confirmed the vulnerability and stated that the fix was applied by validating `restreamerURL` at storage time and re-validating the log-entry branch before use. The maintainer also noted that the `m3u8` field follows the same general pattern but is not server-fetched in the current flow. Proof of concept 1. Log in as a non-admin user with streaming permission. 2. Create a normal restream destination. 3. Trigger `plugin/Live/view/Live_restreams/testRestreamer.json.php` to create a live transmission history row. 4. Call: ```text GET /plugin/Live/view/getRestream.json.php?live_transmitions_history_id=&restreams_id= ``` 5. Extract `tokenForAction` from the returned URL. 6. Exchange it for `responseToken` via: ```text POST /plugin/Live/view/Live_restreams/verifyTokenForAction.json.php ``` 7. Store a loopback callback URL: ```text POST /plugin/Live/view/Live_restreams_logs/add.json.php restreamerURL=http://127.0.0.1:9999/index.php ``` 8. Trigger `getRestream.json.php` again. 9. Observe that the returned response now contains the JSON body from the loopback-only service. Impact An authenticated streamer can cause the AVideo server to send HTTP requests to loopback or internal services and return the response through normal application endpoints by storing a malicious `restreamerURL` in the restream log flow. Because the callback destination was not constrained to trusted restreamer endpoints, the application could be used as a proxy to internal-only services that trust network locality. Successful exploitation can expose local admin panels, internal-only APIs, cloud metadata services if reachable, or other sensitive internal responses available from the application host. Recommended fix • Validate `restreamerURL` against explicitly configured restreamer endpoints at storage time • Re-validate the stored callback URL before server-side fetch • Bind `responseToken` to the expected restream row and callback host • Apply SSRF validation to the initial destination of every server-side fetch, not only redirect targets • Ignore or reject user-supplied callback hosts that do not match trusted configuration