Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Dani-Garcia | Vaultwarden | < 1.35.5 |
Related Weaknesses (CWE)
References
- https://github.com/dani-garcia/vaultwarden/releases/tag/1.35.5ProductRelease Notes
- https://github.com/dani-garcia/vaultwarden/security/advisories/GHSA-x7g7-cgx5-jhExploitVendor Advisory
- https://github.com/dani-garcia/vaultwarden/security/advisories/GHSA-x7g7-cgx5-jhExploitVendor Advisory
FAQ
What is CVE-2026-31835?
CVE-2026-31835 is a vulnerability with a CVSS score of 5.4 (MEDIUM). 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 (1b...
How severe is CVE-2026-31835?
CVE-2026-31835 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-31835?
Check the references section above for vendor advisories and patch information. Affected products include: Dani-Garcia Vaultwarden.