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Reflected XSS via filter parameter

Moderate
9001 published GHSA-8mx2-rjh8-q3jq Jul 30, 2025

Package

pip copyparty (pip)

Affected versions

<=1.18.6

Patched versions

1.18.7

Description

Summary

Unauthorized reflected Cross-Site-Scripting when accessing the URL for recent uploads with the filter parameter containing JavaScript code.

Details

When accessing the recent uploads page at /?ru, users can filter the results using an input field at the top. This field appends a filter parameter to the URL, which reflects its value directly into a <script> block without proper escaping.
This vulnerability allows for reflected Cross-Site Scripting (XSS) and can be exploited against both authenticated and unauthenticated users, enabling unwanted actions in the victims browser.

PoC

A URL like this will execute alert(1):

https://127.0.0.1:3923/?ru&filter=</script><script>alert(1)</script>

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

CVE ID

CVE-2025-54589

Weaknesses

Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as <, >, and & that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. Learn more on MITRE.

Credits