CVE-2026-27898 Vaultwarden: Unauthorized Access via Partial Update API on Another User’s Cipher

Vaultwarden is an unofficial Bitwarden compatible server written in Rust, formerly known as bitwardenrs. Prior to version 1.35.4, an authenticated regular user can specify another user’s cipherid and call "PUT /api/ciphers/id/partial" Even though the standard retrieval API correctly denies access...