Medium severity · published Sep 5, 2026
CVE-2026-83628
Theme My Login <= 7.1.15 - Authenticated (Subscriber+) Missing Authorization to Unauthorized Multisite Subsite Creation via 'gimmeanotherblog' Signup Stage
4.3
CVSS
0.4%
EPSS
No
On KEV
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
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TM
Theme My Login · jfarthing84
through 7.1.15 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-83628
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-83628
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L580
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L661
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L708
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/changeset/3669721/theme-my-login/trunk/includes/ms-functions.php
plugins.trac.wordpress.org
https://plugins.trac.wordpress.org/changeset?old_path=%2Ftheme-my-login/tags/7.1.15&new_path=%2Ftheme-my-login/tags/7.2.0
plugins.trac.wordpress.org
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
More from Theme My Login
9.8
CVE-2026-89079
Theme My Login <= 7.2.1 - Unauthenticated Privilege Escalation via 'user_pass1' POST Parameter in wp_pre_insert_user_data Filter
4.3
CVE-2024-7422
Theme My Login <= 7.1.7 - Cross-Site Request Forgery to Settings Update
