# CVE-2025-55204: muffon has One-click Remote Code Execution via XSS and Custom URL Handling

> An attacker can achieve remote code execution on a victim's machine by tricking them into clicking a malicious custom URL link.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 5 Jan 2026
- **Updated:** 5 Jan 2026
- **Also known as:** GHSA-gc3f-gqph-522q

## What is CVE-2025-55204?

CVE-2025-55204 is a high-severity code injection vulnerability in staniel359 muffon, published on 5 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

muffon is a cross-platform music streaming client for desktop. Versions prior to 2.3.0 have a one-click Remote Code Execution (RCE) vulnerability in. An attacker can exploit this issue by embedding a specially crafted `muffon://` link on any website they control. When a victim visits the site or clicks the link, the browser triggers Muffon’s custom URL handler, causing the application to launch and process the URL. This leads to RCE on the victim's machine without further interaction. Version 2.3.0 patches the issue.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2025-55204?

It affects 1 product.


Products: Muffon Muffon.

## How do I fix CVE-2025-55204?

No fix has been published for CVE-2025-55204 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-55204 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-55204 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-55204 and fix it if it is affected.

What it is: CVE-2025-55204 is a high-severity code injection vulnerability in staniel359 muffon, published on 5 Jan 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-55204 exists.

Affected product: staniel359 muffon. 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-2025-55204/ (Markdown: https://insights.sbomify.com/CVE-2025-55204/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-55204
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-55204
- OSV: https://osv.dev/vulnerability/CVE-2025-55204

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-55204/
Summaries are generated and may contain mistakes; the official description above is the record.