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TI-2026-31977 Aliases CVE-2026-43914

Vaultwarden: Brute-force protection bypass vulnerability

Priority HIGH 81CWE-307Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-307.

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00288 21st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed vaultwarden (dani-garcia): 1.35.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
dani-garciavaultwardenbefore 1.35.41.35.4Patch availableCNA
  • vaultwarden Vendordani-garcia Affected before 1.35.4 Fixed in 1.35.4 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:dani-garcia:vaultwarden:*:*:*:*:*:*:*:*before 1.35.4Vulnerabledani-garcia
  • cpe:2.3:a:dani-garcia:vaultwarden:*:*:*:*:*:*:*:* Versions before 1.35.4 Vulnerable ·dani-garcia

Remediation

  • Fix · CNA vaultwarden (dani-garcia) Fixed in 1.35.4

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43914

References

Exploit 1

Patch 1

Other 1

  • TI-2026-31975 Vaultwarden: Cross-Org Group Binding Enables Unauthorized Read And Write Access Into Another Organization CVSS 3.1HIGH 8.7
  • TI-2026-31974 Vaultwarden: Refresh tokens not invalidated on security stamp rotation CVSS 3.1HIGH 8.1
  • TI-2025-18108 vaultwarden allows escalation of privilege via variable confusion in OrgHeaders trait CVSS 3.1HIGH 8.1
  • TI-2025-18107 vaultwarden allows RCE in the admin panel CVSS 3.1HIGH 7.2
  • TI-2026-22155 Vaultwarden: 2FA Bypass on Protected Actions due to Faulty Rate Limit Enforcement CVSS 4.0MEDIUM 6.0
  • TI-2026-24388 Vaultwarden WebAuthn credential metadata tampered before signature verification CVSS 4.0MEDIUM 5.3
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences