# CVE-2026-66398: phpMyFAQ before 4.1.6 Remote Code Execution via Configuration API

> Authenticated administrators can achieve remote code execution by uploading a malicious ZIP and manipulating configuration settings to extract it into the application root.

- **Severity:** Critical 9.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** GHSA-4fv7-8rr6-rf2w, GHSA-c4f8-v76x-mwx3

## What is CVE-2026-66398?

CVE-2026-66398 is a critical code injection vulnerability in thorsten phpMyFAQ, published on 27 Jul 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

phpMyFAQ before v4.1.6 contains a remote code execution vulnerability in the configuration API that allows authenticated administrators with CONFIGURATION_EDIT and ATTACHMENT_ADD privileges to write arbitrary PHP files by manipulating the upgrade.lastDownloadedPackage setting. Attackers can upload a malicious ZIP file as an attachment, point the updater configuration to its stored path, and extract it into the application root to achieve code execution as the web server user.

Weakness: CWE-494 (Download of Code Without Integrity Check)

## Which versions are affected by CVE-2026-66398?


## How do I fix CVE-2026-66398?

No fix has been published for CVE-2026-66398 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-66398 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66398 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66398 and fix it if it is affected.

What it is: CVE-2026-66398 is a critical code injection vulnerability in thorsten phpMyFAQ, published on 27 Jul 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66398 exists.

Affected product: thorsten phpMyFAQ. 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-2026-66398/ (Markdown: https://insights.sbomify.com/CVE-2026-66398/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66398
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66398
- OSV: https://osv.dev/vulnerability/CVE-2026-66398

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-66398/
Summaries are generated and may contain mistakes; the official description above is the record.