The Advanced Responsive Video Embedder for Rumble, Odysee, YouTube, Vimeo, Kick … plugin for WordPress is vulnerable to Authentication Bypass via a Hardcoded Backdoor in version 10.8.7. The vulnerability exists because the `_arve_uc_init()` function — registered on WordPress's `init` hook at priority 1 so that it runs before any authentication checks on every request — reads an attacker-supplied token from the `_wplogin` (or `_wpm`) parameter and compares it against a hardcoded SHA-256 hash embedded directly in the plugin source, with no nonce verification, no capability check, and no password validation anywhere in the flow. Because this static hash constitutes a set of universal credentials that are publicly accessible in the plugin's source code, unauthenticated attackers can supply the known token to be authenticated as an arbitrarily selected existing administrator account, gaining full administrative control over the affected WordPress site. This was likely introduced by an attacker who gained commit access to the developers account.