CVE-2026-43914
Vaultwarden: Brute-force protection bypass vulnerability
- Published
- May 11, 2026
- Updated
- May 12, 2026
- Assigning CNA
- GitHub_M
- Evidence observed
- Aug 25, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HLow · next 30 days
- Percentile
- 21.6%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
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.
Sources
1PoC for CVE-2026-43914: Vaultwarden <1.35.4 email-2FA brute-force bypass password oracle. Stdlib-only Python.
Responsible use
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