Theme My Login - Broken Access Control (CVE-2026-83628)
CVE-2026-83628
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`.
CVE-2026-83628
MEDIUM
CVSS 4.3
Published 2026-09-05
Updated 2026-09-08
AI Risk Moderate (52/100)
Active Exploit: No strong signal
Published Exploit: No public exploit references
Priority: P4 Planned
Severity Band
MEDIUM
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Affected Components
2
Reference Links
7
AI Risk Engine
Moderate (52/100)
Exploitability
High
Active Exploitation
No strong signal
Published Exploit Status
No public exploit references
AI Context
Machine-generated threat intelligence
AI
Updated 33 days ago
AI enriched 33 days ago (2026-09-06 09:08 UTC)
Technical 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…
Potential Impact
Severity is MEDIUM (CVSS 4.3). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.
Exploitability Assessment
Exploitability is assessed as High based on remote code execution potential, low-bar exploit prerequisites.
Primary risk drivers: remote code execution potential, low-bar exploit prerequisites
Mitigation Recommendations
Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.
Detection & Monitoring
Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.
Business Impact Lens
AI risk score 52/100 (Moderate, High) with priority P4 Planned. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.
