# CVE-2016-8870: Missing authorization in n/a

> Attackers can create user accounts in Joomla even when registration is disabled, bypassing security controls to gain unauthorized access.

- **Severity:** High 8.1 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Nov 2016
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-f3v8-7jfc-xgvg

## What is CVE-2016-8870?

CVE-2016-8870 is a high-severity missing authorization vulnerability in Joomla Joomla\!, published on 4 Nov 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The register method in the UsersModelRegistration class in controllers/user.php in the Users component in Joomla! before 3.6.4, when registration has been disabled, allows remote attackers to create user accounts by leveraging failure to check the Allow User Registration configuration setting.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2016-8870?

It affects 1 product.


Products: Joomla Joomla\!.

## How do I fix CVE-2016-8870?

No fix has been published for CVE-2016-8870 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-8870 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-8870 exists.

Public exploit code:

- Joomla Account Creation and Privilege Escalation (metasploit)
- Joomla! 3.4.4 < 3.6.4 - Account Creation / Privilege Escalation (exploitdb)
- cve-2016-8870 (github_poc): https://github.com/cved-sources/cve-2016-8870

## Other vulnerabilities in Joomla Joomla\!

- [CVE-2016-10033](https://insights.sbomify.com/CVE-2016-10033/): PHPMailer Command Injection (critical 9.8, exploited in the wild)
- [CVE-2023-23752](https://insights.sbomify.com/CVE-2023-23752/): Joomla! Improper Access Control (medium 5.3, exploited in the wild)
- [CVE-2026-48902](https://insights.sbomify.com/CVE-2026-48902/): Joomla! Core - [20260518] - Transport encryption downgrade for password and username reset links (critical 9.8)
- [CVE-2025-25226](https://insights.sbomify.com/CVE-2025-25226/): [20250401] - Joomla Framework - SQL injection vulnerability in quoteNameStr method of Database package (critical 9.8)
- [CVE-2022-23795](https://insights.sbomify.com/CVE-2022-23795/): [20220303] - Core - User row are not bound to a authentication mechanism (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-8870 and fix it if it is affected.

What it is: CVE-2016-8870 is a high-severity missing authorization vulnerability in Joomla Joomla\!, published on 4 Nov 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-8870 exists.

Affected product: Joomla Joomla\!. 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-2016-8870/ (Markdown: https://insights.sbomify.com/CVE-2016-8870/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-8870
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-8870
- OSV: https://osv.dev/vulnerability/CVE-2016-8870

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-8870/
Summaries are generated and may contain mistakes; the official description above is the record.