What’s Vulnerable › Vulnerabilities

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

• Severity: critical (CVSS 9.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-01-05 · updated 2026-10-07
• Weakness: CWE-94

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.

Affected products

• staniel359 muffon: before 2.3.0 — fixed in 2.3.0

How to fix

Upgrade to a fixed version: staniel359 muffon 2.3.0. Check the vendor advisory for mitigations.

References

• https://drive.google.com/file/d/1eCPCQ6leuVM_vecfofFv04c0t9isCBqR/view?usp=sharing
• https://github.com/staniel359/muffon/releases/tag/v2.3.0
• https://github.com/staniel359/muffon/security/advisories/GHSA-gc3f-gqph-522q

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