WordPressプラグイン「Support Genix – Helpdesk, AI Chatbot, Knowledge Base & Customer Support Ticketing System」に不適切な認証の脆弱性（CVE-2026-19806）

The Support Genix – Helpdesk, AI Chatbot, Knowledge Base & Customer Support Ticketing System plugin for WordPress is vulnerable to Authentication Bypass leading to Administrator Account Takeover in all versions up to, and including, 1.4.52 via the `guest_ticket_login()` function and its `p` parameter. This is due to the site-wide AES-256-CBC encryption key being derived from only three two-digit `wp_rand(10, 99)` values and a Unix timestamp via `md5()` — yielding approximately 19.5 bits of entropy — combined with a deterministic IV derived from the password, no authentication tag on the ciphertext, and no capability check, nonce, or session validation on the publicly reachable `/sgnix/?p=<token>` endpoint. This makes it possible for authenticated attackers, with subscriber-level access and above, who can obtain a single legitimate guest ticket token as a known-plaintext oracle and bound the plugin activation timestamp, to exhaust the ~729,000-candidate keyspace entirely offline, recover the site-wide encryption key, and forge a self-consistent `{ticket_id, ticket_user}` token targeting any administrator-owned ticket. Submitting the forged token to the unprotected endpoint causes `wp_set_auth_cookie()` to be called for that administrator, granting the attacker full administrative access to the WordPress site.