CVE-2026-27898 MEDIUM

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

Vendor Dani-Garcia
Product vaultwarden
Weakness CWE-639 · IDOR
Published March 4, 2026
Last update March 5, 2026

CVSS base score

5.4/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

What the vulnerability does

01Description

Vaultwarden is an unofficial Bitwarden compatible server written in Rust, formerly known as bitwarden_rs. Prior to version 1.35.4, an authenticated regular user can specify another user’s cipher_id and call "PUT /api/ciphers/{id}/partial" Even though the standard retrieval API correctly denies access to that cipher, the partial update endpoint returns 200 OK and exposes cipherDetails (including name, notes, data, secureNote, etc.). This issue has been patched in version 1.35.4.

Key dates

02Disclosure timeline

March 4, 2026 CVE published
March 5, 2026 Record updated