CVE-2026-83628 json
Theme My Login <= 7.1.15 - Authenticated (Subscriber+) Missing Authorization to Unauthorized Multisite Subsite Creation via 'gimmeanotherblog' Signup Stage
published 2026-09-05 2 mo ago modified 2026-09-08 2 mo ago also EUVD-2026-71840
- cvss
- 4.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 33%
- public exploits
- 0
- none known
Summary
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`.
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
Affected products
- jfarthing84 Theme My Login
Classification
- Weakness
-
- CWE-862 Missing Authorization
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/72585c12-baa9-4c63-8584-906a1d3b332f?source=cve
- plugins.trac.wordpress.org /browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L708
- plugins.trac.wordpress.org /browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L661
- plugins.trac.wordpress.org /browser/theme-my-login/tags/7.1.15/includes/ms-functions.php#L580
- plugins.trac.wordpress.org /changeset?reponame=&new=3669722%40theme-my-login%2Ftags%2F7.2.0&old=3643898%40theme-my-login%2Ftags%2F7.1.15
- plugins.trac.wordpress.org /changeset/3669721/theme-my-login/trunk/includes/ms-functions.php
- plugins.trac.wordpress.org /changeset?old_path=%2Ftheme-my-login/tags/7.1.15&new_path=%2Ftheme-my-login/tags/7.2.0
Sources
- CVE List CVE-2026-83628
- NVD CVE-2026-83628
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.