# CVE-2026-5131: Server-Side Request Forgery in GREENmod

> An attacker can exploit incorrect named pipe permissions to perform Server-Side Request Forgery, potentially executing code or reading data on Windows systems.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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:** 17 Apr 2026
- **Updated:** 17 Apr 2026
- **Also known as:** GHSA-f2cg-3cww-mcq8

## What is CVE-2026-5131?

CVE-2026-5131 is a medium-severity server-side request forgery vulnerability in Nomios Poland GREENmod, published on 17 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

GREENmod uses named pipes for communication between plugins, the web portal, and the system service, but the access control lists for these pipes are configured incorrectly. This allows an attacker to communicate with the stream and upload any XML or JSON file, which will be processed by the named pipe with the privileges of the user under whose context the service is running. This allows for Server-Side Request Forgery to any Windows system on which the agent is installed and which provides communication via SMB or WebDav.

This issue was fixed in version 2.8.33.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-5131?


## How do I fix CVE-2026-5131?

No fix has been published for CVE-2026-5131 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-5131 being exploited?

There is no known exploitation of CVE-2026-5131 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5131 and fix it if it is affected.

What it is: CVE-2026-5131 is a medium-severity server-side request forgery vulnerability in Nomios Poland GREENmod, published on 17 Apr 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-2026-5131 in the wild and no public exploit code.

Affected product: Nomios Poland GREENmod. 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-2026-5131/ (Markdown: https://insights.sbomify.com/CVE-2026-5131/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5131
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5131
- OSV: https://osv.dev/vulnerability/CVE-2026-5131

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5131/
Summaries are generated and may contain mistakes; the official description above is the record.