CVE-2026-33719: AVideo: Unauthenticated CDN Configuration Takeover via Empty Default Key Bypass and Mass-Assignment

The CDN plugin endpoints plugin/CDN/status.json.php and plugin/CDN/disable.json.php use key-based authentication with an empty string default key. When the CDN plugin is enabled but the key has not been configured (the default state), the key validation check is completely bypassed, allowing any unauthenticated attacker to modify the full CDN configuration — including CDN URLs, storage credentials, and the authentication key itself — via mass-assignment through the par request parameter.