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Stored XSS in search no result messages

Moderate
alistair3149 published GHSA-86xf-2mgp-gv3g Jun 11, 2025

Package

Citizen (MediaWiki)

Affected versions

>= a0296afaedbe1a277337a2d8f1da83cb3a79b9ab

Patched versions

93c36ac778397e0e7c46cf7adb1e5d848265f1bd

Description

Summary

The citizen-search-noresults-title and citizen-search-noresults-desc system messages are inserted into raw HTML, allowing anybody who can edit those messages to insert arbitrary HTML into the DOM.

Details

The system messages are inserted as raw HTML by the mustache template:

mediawiki-skins-Citizen/resources/skins.citizen.search/templates/TypeaheadPlaceholder.mustache

Lines 8 to 9 in 407052e

{{#title}}<div class="citizen-typeahead-placeholder-title">{{{.}}}</div>{{/title}}
{{#description}}<div class="citizen-typeahead-placeholder-description">{{{.}}}</div>{{/description}}

PoC

  1. Edit citizen-search-noresults-title and citizen-search-noresults-desc to <img src="" onerror="alert('citizen-search-noresults-title')"> and <img src="" onerror="alert('citizen-search-noresults-desc')"> (script tags don't work here due to the way the HTML is inserted)
  2. Open the search bar and search for a page that doesn't exist to get the "no results" messages to show up

image
image

Impact

This impacts wikis where a group has the editinterface but not the editsitejs user right.

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-2025-49576

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