Vulnerability Report

CVE-2026-43914

Title: Vaultwarden Brute-Force Protection Bypass

Auth Bypass

Proof Of Concept

PoC Available for CVE-2026-43914

CWE Category CWE-307
Published Date May 11, 2026
Modified Date May 13, 2026
Exploit Status Available
Score 7.3 CVSS v3.1
Exploit Probability (EPSS)
0.49%

Vulnerability Summary

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.

Impacted Vendors

D
dani-garcia 1

Reference Links

https://github.com/dani-garcia/vaultwarden/pull/6867 https://github.com/dani-garcia/vaultwarden/releases/tag/1.35.4 https://github.com/dani-garcia/vaultwarden/security/advisories/GHSA-c5rv-q295-7w4g
CVSS v3.1
Source Entity [email protected]
Severity CRITICAL
9.8
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.3
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-43914 Exploits & PoCs (Proof Of Concept)

GitHub https://github.com/Boreas37/CVE-2026-43914-PoC
View Code
MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Stack

No specific products linked.