CVE intelligence and bounded remediation

CVE-2026-31835 — Vaultwarden is a Bitwarden-compatible server written in Rust

Medium CVSS 5.4

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.

Severity
Medium
CVSS
5.4 (3.1)
Published
2026-05-05
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-345

Affected products

  • dani-garcia / vaultwarden

Matched remediation archetype

Supply-chain, dependency, build, and update integrity

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace affected packages, source archives, build actions, plugins, installers, and updates from declared source to deployed artifact.
  • Confirm provenance, signatures or digests, namespace ownership, lockfile resolution, registry configuration, and build-runner trust boundaries.
  • Inventory direct, transitive, vendored, generated, and bundled copies across releases and distribution channels.

Remediate safely

  • Move to a maintained trusted artifact or remove the dependency; pin immutable identities and verify provenance and integrity before use.
  • Regenerate lockfiles and artifacts in a clean isolated build, minimize build credentials and network access, and produce an updated software bill of materials.
  • Require reviewed update policy, protected publishing, and reproducible or independently attestable builds where supported.

Authoritative sources

Complete CVE record and remediation plan

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