CVE-2026-31835
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.
- Affected products
- Vaultwarden
- Dani-garcia Vaultwarden
- < 1.35.5
- Fix
- Available
- CVSS 3.1
- 5.4 MEDIUM
- EPSS
- 0.2% (5th percentile)
- Weakness
- CWE-345
- NVD status
- Analyzed
- Published
- 2026-05-05
No indexed exploits for CVE-2026-31835 yet
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