AVideo - Arbitrary User Session Hijacking via Meet Plugin uploadRecordedVideo Endpoint

AVideo through 29.0 contains an authorization bypass vulnerability in the Meet plugin's uploadRecordedVideo.json.php endpoint that derives the target users_id from the uploaded filename without verification. An attacker with knowledge of the Meet shared secret can craft a malicious file upload with a filename containing an arbitrary users_id to invoke passwordless User->login() and establish an authenticated session as any user including admin. Attackers can obtain the Meet shared secret through path-traversal vulnerabilities or timing attacks against checkToken.json.php, then POST a crafted file to uploadRecordedVideo.json.php with a filename like '1-anything.mp4' to hijack admin sessions and gain full account takeover.