Lychee is a free, open-source photo-management tool. Prior to 7.6.1, POST /api/v2/Album::unlock has no throttle, attempt counter, backoff, CAPTCHA, or lockout. UnlockAlbumRequest::authorize() permits any caller to submit attempts, and app/Actions/Album/Unlock.php verifies each guess with Hash::check without limiting repeated failures. A remote unauthenticated attacker who knows or can obtain an album identifier can automate password guesses against a password-protected album and, if the password is recovered, gain access to its private photo collection. This issue is fixed in version 7.6.1.