# CVE-2026-83628: Missing authorization in Theme My Login

> Authenticated subscribers can bypass registration policies to create unauthorized subsites and gain administrator privileges on those new sites.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Sep 2026
- **Updated:** 7 Sep 2026
- **Also known as:** GHSA-6vjm-3j93-7v9p

## What is CVE-2026-83628?

CVE-2026-83628 is a medium-severity missing authorization vulnerability in jfarthing84 Theme My Login, published on 5 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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`.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-83628?


## How do I fix CVE-2026-83628?

No fix has been published for CVE-2026-83628 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-83628 being exploited?

There is no known exploitation of CVE-2026-83628 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-83628 and fix it if it is affected.

What it is: CVE-2026-83628 is a medium-severity missing authorization vulnerability in jfarthing84 Theme My Login, published on 5 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-83628 in the wild and no public exploit code.

Affected product: jfarthing84 Theme My Login. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-83628/ (Markdown: https://insights.sbomify.com/CVE-2026-83628/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-83628
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-83628
- OSV: https://osv.dev/vulnerability/CVE-2026-83628

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-83628/
Summaries are generated and may contain mistakes; the official description above is the record.