CVE-2026-70556: Hubzilla 11.2.1 CSRF via OAuth2 /authorize Endpoint App Registration

Hubzilla 11.2.1 contains a cross-site request forgery vulnerability in the OAuth2 /authorize endpoint handled by Zotlabs\Module\Authorize::post() that allows unauthenticated attackers to register arbitrary OAuth2 applications under an authenticated user's account by submitting a cross-origin POST request without CSRF token or Origin/Referer validation. Attackers can craft a malicious HTML form that autosubmits attacker-chosen OAuth2 parameters including clientid, clientsecret, redirecturi, and scope to silently register a persistent OAuth2 application, enabling interception of future OAuth2 authorization codes when the victim later authenticates against the attacker-controlled client.