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.
- 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
- None listed
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.
Which versions are affected by CVE-2025-55204?
It affects 1 product.
Products include 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.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2025-55204 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-55204 exists.
Sources
Also known as GHSA-gc3f-gqph-522q.