# CVE-2026-85520: Unauthenticated arbitrary file write leading to RCE in gmfeed PrestaShop module

> Unauthenticated attackers can write arbitrary files to the server via the feed.php endpoint, leading to remote code execution.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-mxmh-vx83-qfxg

## What is CVE-2026-85520?

CVE-2026-85520 is a critical vulnerability in MyPresta Google Merchant Center Feed, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Google Merchant Center Feed (gmfeed) module for PrestaShop is vulnerable to unauthenticated arbitrary file write in the feed.php endpoint. An unauthenticated attacker can send a crafted request that controls the output file name, path, extension, and content through request parameters. Due to the lack of authentication and input validation, the request is processed successfully, allowing an attacker to write and execute arbitrary PHP code, resulting in remote code execution (RCE).

This issue was fixed in version 2.3.9.

Weakness: CWE-73 (External Control of File Name or Path)

## Which versions are affected by CVE-2026-85520?


## How do I fix CVE-2026-85520?

No fix has been published for CVE-2026-85520 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85520 being exploited?

There is no known exploitation of CVE-2026-85520 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-85520 PoC (PoCbit) — PrestaShop MyPresta gmfeed ≤2.3.9 unauthenticated arbitrary file write via feed.php (Save to file URL) → RCE. check + exploit + mass bulk (--list -j). https://pocbit.org/pocs/cve-2026-85520 (github_poc): https://github.com/murrez/CVE-2026-85520

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85520 and fix it if it is affected.

What it is: CVE-2026-85520 is a critical vulnerability in MyPresta Google Merchant Center Feed, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-85520 in the wild and no public exploit code.

Affected product: MyPresta Google Merchant Center Feed. 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-2026-85520/ (Markdown: https://insights.sbomify.com/CVE-2026-85520/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85520
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85520
- OSV: https://osv.dev/vulnerability/CVE-2026-85520

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85520/
Summaries are generated and may contain mistakes; the official description above is the record.