Is this vulnerability remotely exploitable over the internet?

Yes. An attacker can host or send a malicious `muffon://` link that, when opened on a system with Muffon installed and registered as a handler, can lead to remote code execution. The attacker does not need network-level access to the victim beyond the ability to deliver the link.

What level of access does an attacker need to exploit this issue?

The attacker only needs to convince the user to visit a web page or open content capable of invoking a `muffon://` link. They do not require local filesystem or shell access. The code that runs will typically execute with the privileges of the user account running Muffon.

What is the safest general fix pattern for developers?

The safest approach is to redesign the custom URL handler so that it never uses URL data directly in any form of code, command, or script execution. Inputs from the `muffon://` scheme should be strictly parsed, validated against an allowlist, and mapped to a small set of safe, predefined actions without dynamic behavior.

Severity:

HIGH RISK

(8.8)

One-Click RCE via Custom URL Handler (CWE-94) in Muffon Music Client

CVE-2025-55204

Published:

Jan 5, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

Remote Code Execution on the Router

April 6, 2026

CWE-77;CWE-78

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Remote Code Execution on Router Firmware

April 6, 2026

Vulnerability Type

Category:

Code Injection / Remote Code Execution

CWE:

CWE-94;CWE-79

Impact:

Remote Code Execution on Client Systems

Severity:

HIGH RISK

(8.8)

CVSS Version:

3.1

Vulnerability Type

Category:

Code Injection / Remote Code Execution

CWE:

CWE-94;CWE-79

Impact:

Remote Code Execution on Client Systems

Severity:

HIGH RISK

(8.8)

CVSS Version:

3.1

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355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

One-Click RCE via Custom URL Handler (CWE-94) in Muffon Music Client

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setGameSpeedCfg CGI Handler

HIGH RISK

HIGH

(7.3)

OS Command Injection (CWE-78) in Totolink A7100RU setFirewallType Handler

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

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