Vaultwarden: SSO Email Auto-Link Can Bind an Existing Local Account to an Attacker-Controlled IdP Identity

Vaultwarden is a Bitwarden-compatible server written in Rust. Prior to 1.36.0, Vaultwarden's SSO login flow checked the IdP email_verified claim only for new-user creation and not when SSO_SIGNUPS_MATCH_EMAIL=true linked an IdP identity to an existing local account, allowing an attacker-controlled IdP identity asserting a victim email address to bind to and authenticate as that account. This issue is fixed in version 1.36.0.