CVE-2026-96765: WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) <= 44.1 - Unauthenticated Stored Cross-Site Scripting via 'id_token' Parameter (iss / unique_name JWT claims)

The WPO365 | SEAMLESS WORDPRESS + MICROSOFT INTEGRATION (WPO365 | LOGIN) plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'id_token' parameter in all versions up to, and including, 44.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload is stored in the wpo365_errors transient for up to three days by submitting a crafted unauthenticated request with a forged id_token whose base64url-decoded unique_name or iss claim contains malicious HTML, requiring no prior authentication or user interaction beyond an administrator later visiting the WPO365 wizard page.