CVE-2025-55204 – One-Click Remote Code Execution in Muffon

CyberDefender 3 mins0

Severity: Critical / High (CVSS 3.1 8.8)
Product: muffon — a cross-platform desktop music streaming client
Affected Versions: All versions prior to 2.3.0
Patched Version: 2.3.0 and later
CWE: CWE-94 Improper Control of Code Generation (‘Code Injection’)

Vulnerability Overview

Attacker can achieve Remote Code Execution (RCE) with minimal interaction:

  • Muffon registers a custom URL scheme (muffon://).
  • If a user visits a malicious webpage or clicks a crafted muffon:// link, the browser invokes Muffon’s URL handler.
  • The application processes the URL without sanitizing/validating input, leading to arbitrary code execution on the victim’s machine under the user’s privilege level.

This qualifies as a “one-click RCE” because the exploit only requires visiting a malicious link, and no additional authentication or complex steps are necessary.

Typical Exploit Scenario

  1. Attacker crafts malicious muffon:// link with embedded commands or payload.
  2. Victim is tricked into visiting a site or clicking the link.
  3. Browsers launch Muffon with the payload.
  4. The application executes the payload due to unsafe URL handling.

Successful exploitation can lead to:

  • Full compromise of the user session or system.
  • Arbitrary code execution (installing malware, data theft, persistence).
  • Execution with the privileges of the logged-in user (can be admin).

Because this vector involves a URL handler, typical vectors include phishing, malicious advertising, or compromised websites.

Mitigation & Remediation

  1. Update Immediately:
    Upgrade Muffon to version 2.3.0 or newer — this version contains the fix that properly sanitizes and validates custom URL handler input.
  2. User Awareness:
    Educate users to avoid clicking untrusted or unfamiliar links, especially those using uncommon URL schemes.
  3. Network/Endpoint Controls:
    • If possible, block or monitor muffon:// URL handling.
    • Use endpoint protection/EDR tools to detect anomalous process launches triggered by custom URL handlers.
  4. Web Filtering / Safe Browsing:
    Block access to known malicious domains and phishing vectors that might serve malicious muffon:// links.

CyberDefender