CVE-2026-86461: CWE-434 Unrestricted Upload of File with Dangerous Type in foliovision FV Flowplayer Video Player

The FV Flowplayer Video Player plugin for WordPress is vulnerable to Limited Arbitrary File Upload in all versions up to, and including, 7.5.54.7212 via the check_mimetype function. This is due to incomplete file type validation in the check_mimetype function — while some extension checking is present, it can be bypassed, allowing attacker-supplied remote file content to be written with insufficient extension enforcement and no MIME check or WordPress upload helper. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible. Exploitation requires the plugin's 'profile videos on bio' option to be enabled, as this causes the nonce to be emitted on the subscriber-accessible profile page; without this setting, authenticated users below Editor cannot obtain the required nonce.