# CVE-2016-20053: Redaxo CMS 5.2 Cross-Site Request Forgery via users endpoint

> Attackers can create admin accounts via CSRF by tricking administrators into visiting malicious pages, leading to privilege escalation.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Apr 2026
- **Updated:** 6 Apr 2026
- **Also known as:** GHSA-2r3p-9jrg-pvg9

## What is CVE-2016-20053?

CVE-2016-20053 is a medium-severity vulnerability in Redaxo CMS, published on 4 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Redaxo CMS 5.2 contains a cross-site request forgery vulnerability that allows unauthenticated attackers to create administrative user accounts by tricking authenticated administrators into visiting malicious pages. Attackers can craft HTML forms targeting the users endpoint with hidden fields containing admin credentials and account parameters to add new administrator accounts without user consent.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2016-20053?

It affects 1 product.


Products: Redaxo Redaxo.

## How do I fix CVE-2016-20053?

No fix has been published for CVE-2016-20053 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-20053 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-20053 exists.

## Other vulnerabilities in Redaxo CMS

- [CVE-2018-18200](https://insights.sbomify.com/CVE-2018-18200/): SQL injection in n/a (critical 9.8)
- [CVE-2018-17831](https://insights.sbomify.com/CVE-2018-17831/): SQL injection in n/a (critical 9.8)
- [CVE-2026-21857](https://insights.sbomify.com/CVE-2026-21857/): Redaxo has Path Traversal in Backup Addon Leading to Arbitrary File Read (high 8.3)
- [CVE-2006-2843](https://insights.sbomify.com/CVE-2006-2843/): Code injection in n/a (high 7.5)
- [CVE-2006-2844](https://insights.sbomify.com/CVE-2006-2844/): Multiple PHP remote file inclusion vulnerabilities in Redaxo 3.0 allow remote attackers to execute arbitrary PHP code via a URL in the REX[I (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-20053 and fix it if it is affected.

What it is: CVE-2016-20053 is a medium-severity vulnerability in Redaxo CMS, published on 4 Apr 2026. 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-2016-20053 exists.

Affected product: Redaxo CMS. 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-2016-20053/ (Markdown: https://insights.sbomify.com/CVE-2016-20053/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-20053
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-20053
- OSV: https://osv.dev/vulnerability/CVE-2016-20053

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-20053/
Summaries are generated and may contain mistakes; the official description above is the record.