WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) <= 44.1 - Unauthenticated Authentication Bypass via OIDC Nonce Replay via id_token Nonce Verification

Summary

The WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) plugin for WordPress is vulnerable to Authentication Bypass via OIDC Nonce Replay in all versions up to, and including, 44.1 This is due to `Id_Token_Service_Deprecated::process_openidconnect_token()` using the incompatible WordPress core `wp_verify_nonce()` function to validate a nonce produced by `Nonce_Service::create_nonce()` — a 64-character hex value that `wp_verify_nonce()` can never successfully verify — causing the nonce check to silently fail without terminating authentication, so execution continues into `authenticate_oidc_user()` with the attacker-supplied `id_token`. This makes it possible for unauthenticated attackers who have obtained a previously-issued, valid `id_token` for a target account to replay that token and authenticate as any WordPress user, including administrators, resulting in full site takeover. This vulnerability is only exploitable when the `use_id_token_parser_v2` plugin option is enabled, as this is the configuration that routes token processing through the deprecated parser containing the broken nonce check.

Timeline

1. Oct 10, 2026, 7:41 AM UTCCVE published
2. Oct 11, 2026, 4:37 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 11, 2026, 4:55 PM UTCRecord last updated

Affected versions

• wpo365 WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN)

  through 44.1

References 7