CVE-2026-83628

Description

The Theme My Login plugin for WordPress is vulnerable to Missing Authorization in versions up to, and including, 7.1.15 on Multisite installations. This is due to the `tml_ms_signup_handler()` function's `gimmeanotherblog` branch failing to enforce the network's `active_signup` registration policy, checking only `is_user_logged_in()` while sibling branches such as `validate-blog-signup` apply the full policy gate. This makes it possible for authenticated attackers, with Subscriber-level access and above, to directly POST `stage=gimmeanotherblog` to Theme My Login's signup route, bypassing the configured registration policy entirely — even when it is set to `none` or `user` — which causes `wpmu_create_blog()` to execute with the attacker's user ID, after which WordPress core assigns the Administrator role on the newly created subsite via `add_user_to_blog()`. The privilege gain is scoped to the newly created subsite only; the attacker's account retains Subscriber-level access on the main site and does not obtain Super Admin or network-level capabilities such as `manage_network` or `manage_sites`.

CVSS Vector

References

• https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L580
• https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L661
• https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L708
• https://plugins.trac.wordpress.org/changeset/3669721/theme-my-login/trunk/includes/ms-functions.php
• https://plugins.trac.wordpress.org/changeset?old_path=%2Ftheme-my-login/tags/7.1.15&new_path=%2Ftheme-my-login/tags/7.2.0
• https://plugins.trac.wordpress.org/changeset?reponame=&new=3669722%40theme-my-login%2Ftags%2F7.2.0&old=3643898%40theme-my-login%2Ftags%2F7.1.15
• https://www.wordfence.com/threat-intel/vulnerabilities/id/72585c12-baa9-4c63-8584-906a1d3b332f?source=cve