# CVE-2026-6257: Vvveb CMS < v1.0.8.2 Remote Code Execution via Media Management

> Authenticated attackers can rename uploaded files to executable extensions to achieve remote code execution in Vvveb CMS.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Apr 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-c9rc-p9cp-2x7q

## What is CVE-2026-6257?

CVE-2026-6257 is a critical vulnerability in Vvveb CMS, published on 20 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Vvveb CMS before 1.0.8.2 contains a remote code execution vulnerability in its media management functionality where a missing return statement in the file rename handler allows authenticated attackers to rename files to blocked extensions .php or .htaccess. Attackers can exploit this logic flaw by first uploading a text file and renaming it to .htaccess to inject Apache directives that register PHP-executable MIME types, then uploading another file and renaming it to .php to execute arbitrary operating system commands as the www-data user.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2026-6257?


## How do I fix CVE-2026-6257?

No fix has been published for CVE-2026-6257 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6257 being exploited?

There is no known exploitation of CVE-2026-6257 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6257 and fix it if it is affected.

What it is: CVE-2026-6257 is a critical vulnerability in Vvveb CMS, published on 20 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-6257 in the wild and no public exploit code.

Affected product: Vvveb 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-2026-6257/ (Markdown: https://insights.sbomify.com/CVE-2026-6257/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6257
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6257
- OSV: https://osv.dev/vulnerability/CVE-2026-6257

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6257/
Summaries are generated and may contain mistakes; the official description above is the record.