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Stored XSS in preference menu heading messages

Moderate
alistair3149 published GHSA-jwr7-992g-68mh Jun 11, 2025

Package

Citizen (MediaWiki)

Affected versions

>= a741639085d70c22a9f49890542a142a223bf981

Patched versions

93c36ac778397e0e7c46cf7adb1e5d848265f1bd

Description

Summary

Various preferences messages are inserted into raw HTML, allowing anybody who can edit those messages to insert arbitrary HTML into the DOM.

Details

The innerHtml of the label div is set to the textContent of the label, essentially unsanitizing the system messages:

mediawiki-skins-Citizen/resources/skins.citizen.preferences/addPortlet.polyfill.js

Line 18 in 407052e

labelDiv.innerHTML = label.textContent || '';

PoC

  1. Edit citizen-feature-custom-font-size-name (or any other message displayed in a heading in the preferences menu) to <img src="" onerror="alert('citizen-feature-custom-font-size-name')"> (script tags don't work here due to the way the HTML is inserted)
  2. Open the preferences menu
    image

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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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:H/UI:N/S:U/C:H/I:H/A:N

CVE ID

CVE-2025-49577

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Learn more on MITRE.

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