4.3
MEDIUM CVSS 3.1
CVE-2026-83628
Theme My Login <= 7.1.15 - Authenticated (Subscriber+) Missing Authorization to Unauthorized Multisite Subsite Creation via 'gimmeanotherblog' Signup Stage
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`.

INFO

Published Date :

Sept. 5, 2026, 6:17 a.m.

Last Modified :

Sept. 5, 2026, 6:17 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-83628 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
Solution
Update the Theme My Login plugin to a version that addresses the authorization bypass vulnerability.
  • Update the Theme My Login plugin to the latest version.
  • Verify plugin configuration on Multisite installations.
  • Review user roles and permissions on subsites.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-83628 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-83628 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-83628 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-83628 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Sep. 05, 2026

    Action Type Old Value New Value
    Added 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`.
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
    Added CWE CWE-862
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/83xxx/CVE-2026-83628.json">CVE-2026-83628</a>
    Added Reference https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L580
    Added Reference https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L661
    Added Reference https://plugins.trac.wordpress.org/browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L708
    Added Reference https://plugins.trac.wordpress.org/changeset/3669721/theme-my-login/trunk/includes/ms-functions.php
    Added Reference https://plugins.trac.wordpress.org/changeset?old_path=%2Ftheme-my-login/tags/7.1.15&new_path=%2Ftheme-my-login/tags/7.2.0
    Added Reference 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
    Added Reference https://www.wordfence.com/threat-intel/vulnerabilities/id/72585c12-baa9-4c63-8584-906a1d3b332f?source=cve
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.