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CVE-2026-43914

Vaultwarden: Brute-force protection bypass vulnerability

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 1.35.4
1 proof of concept on GitHub
  • Exploitation: poc
  • Automatable: yes
  • Technical impact: partial

Summary

Vaultwarden is a Bitwarden-compatible server written in Rust. Prior to 1.35.4, there is a security vulnerability in Vaultwarden that allows bypassing the login brute-force protection if email 2fa is enabled. If email 2fa is enabled, the unprotected 2fa-function send_email_login (email.rs, api endpoint /api/two-factor/send-email-login) also acts as an oracle determining whether a username-password combination is correct. An attacker can abuse that endpoint to brute-force passwords without rate-limiting. This works even for users who don't have email 2fa configured. This vulnerability is fixed in 1.35.4.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • dani-garcia vaultwarden

    fixed in 1.35.4

References 4

GitHub · dani-garcia/vaultwarden

GitHub · Boreas37/CVE-2026-43914-PoC