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TI-2026-24388 Aliases CVE-2026-31835

Vaultwarden WebAuthn credential metadata tampered before signature verification

Priority MEDIUM 57CWE-345Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-345.

Summary

Vaultwarden is a Bitwarden-compatible server written in Rust. In versions 1.35.4 and earlier, the WebAuthn authentication flow in `validate_webauthn_login()` updates persistent credential metadata (1backup_eligible1 and 1backup_state flags1) based on unverified `authenticatorData` before signature validation is performed. An attacker who knows a user's password but cannot produce a valid WebAuthn signature can permanently modify the stored backup flags for that user's credential. If signature verification fails, the database update is not rolled back. This can result in a persistent denial of service of WebAuthn two-factor authentication for affected credentials. This issue has been fixed in version 1.35.5.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00151 4th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed vaultwarden (dani-garcia): 1.35.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
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 1.35.51.35.5Patch availableCNA
  • vaultwarden Vendordani-garcia Affected before 1.35.5 Fixed in 1.35.5 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:dani-garcia:vaultwarden:*:*:*:*:*:*:*:*before 1.35.5Vulnerabledani-garcia
  • cpe:2.3:a:dani-garcia:vaultwarden:*:*:*:*:*:*:*:* Versions before 1.35.5 Vulnerable ·dani-garcia

Remediation

  • Fix · CNA vaultwarden (dani-garcia) Fixed in 1.35.5

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-2026-31835

References

Exploit 1

Other 1

  • TI-2026-31977 Vaultwarden: Brute-force protection bypass vulnerability CVSS 3.1CRITICAL 9.8
  • 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
See all 19 →

Sources

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