CVE-2026-31835 Vaultwarden WebAuthn credential metadata tampered before signature verification
Attackers can permanently disable WebAuthn two-factor authentication for users by tampering with credential metadata before signature verification occurs.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-31835?
CVE-2026-31835 is a medium-severity vulnerability in dani-garcia vaultwarden, published on 5 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-345
Which versions are affected by CVE-2026-31835?
It affects 1 product.
Products include Dani-Garcia Vaultwarden.
How do I fix CVE-2026-31835?
No fix has been published for CVE-2026-31835 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-31835 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31835 exists.
Other vulnerabilities in dani-garcia vaultwarden
- CVE-2024-55225 Vaultwarden vulnerable to user impersonation
- CVE-2024-55224 Vaultwarden HTML injection vulnerability
- CVE-2024-39924 Privilege escalation in n/a
- CVE-2026-43912 Vaultwarden: Cross-Org Group Binding Enables Unauthorized Read And Write Access Into Another Organization
- CVE-2026-27802 Vaultwarden: Privilege Escalation via Bulk Permission Update to Unauthorized Collections by Manager
Sources
Also known as GHSA-x7g7-cgx5-jhx2.