CVE-2026-43914

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.

Affected products

Vaultwarden

Dani-garcia Vaultwarden

< 1.35.4

Fix

Available

CVSS 3.1

9.8 CRITICAL

EPSS

0.3% (21th percentile)

Weakness

CWE-307

NVD status

Analyzed

Published

2026-05-11