CVE-2026-31835 Details
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.
A vulnerability in Vaultwarden, a Bitwarden-compatible server written in Rust, allows for persistent tampering of WebAuthn credential backup metadata in versions through 1.35.4. The issue arises because the WebAuthn authentication process updates credential flags based on unverified data before validating signatures. An attacker who knows a user's password but cannot provide a valid WebAuthn signature can exploit this flaw to permanently alter the backup eligibility and state flags of the user's credential. As a result, WebAuthn two-factor authentication becomes permanently disabled for the affected credentials, causing a denial-of-service condition.
Users can upgrade to Vaultwarden version 1.35.5, which addresses this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 6, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/dani-garcia/vaultwarden/security/advisories/GHSA-x7g7-cgx5-jhx2 | CISA-ADP | ExploitVendor Advisory |
| https://github.com/dani-garcia/vaultwarden/releases/tag/1.35.5 | [email protected] | ProductRelease Notes |
| https://github.com/dani-garcia/vaultwarden/security/advisories/GHSA-x7g7-cgx5-jhx2 | [email protected] | ExploitVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-345 | Insufficient Verification of Data Authenticity | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| dani-garcia vaultwarden | < 1.35.5 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 25, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 11, 2026 | Initial Analysis | [email protected] |
| May 6, 2026 | CVE Modified | CISA-ADP |
| May 5, 2026 | New CVE Received | [email protected] |