Critical severity · published May 11, 2026
CVE-2026-43914
Vaultwarden: Brute-force protection bypass vulnerability
9.8
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
VA
vaultwarden · dani-garcia
< 1.35.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-43914
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-43914
Issue Tracking
https://github.com/dani-garcia/vaultwarden/pull/6867
Product
https://github.com/dani-garcia/vaultwarden/releases/tag/1.35.4
Exploit
https://github.com/dani-garcia/vaultwarden/security/advisories/GHSA-c5rv-q295-7w4g
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