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Fencer Intel
high 8.8

CVE-2025-55204 json

muffon has One-click Remote Code Execution via XSS and Custom URL Handling

published 10mo ago modified last mo. also EUVD-2025-206240

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits
0
none known

Summary

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.

Patch / fix

  • muffon muffon 2.3.0

Is CVE-2025-55204 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
10mo ago

Exploit prediction

0.72% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/staniel359/muffon/security/advisories/GHSA-gc3f-gqph-522q referenced PoC, tagged "exploit" by a source, unverified
  • drive.google.com https://drive.google.com/file/d/1eCPCQ6leuVM_vecfofFv04c0t9isCBqR/view?usp=sharing referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 9.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected products

  • staniel359 muffon

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.