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.

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History

Tue, 05 May 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Dani-garcia
Dani-garcia vaultwarden
Vendors & Products Dani-garcia
Dani-garcia vaultwarden

Tue, 05 May 2026 19:00:00 +0000

Type Values Removed Values Added
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.
Title Vaultwarden WebAuthn credential metadata tampered before signature verification
Weaknesses CWE-345
References
Metrics cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-05T18:51:35.457Z

Reserved: 2026-03-09T17:41:56.078Z

Link: CVE-2026-31835

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-05T19:16:21.733

Modified: 2026-05-05T19:16:21.733

Link: CVE-2026-31835

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-05T20:30:31Z

Weaknesses