CVE-2026-100243
Received Received - Intake

Stored XSS in MediaWiki WikiSEO Extension

Publication date: 2026-09-29

Last updated on: 2026-09-29

Assigner: wikimedia-foundation

Description
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation Mediawiki - WikiSEO Extension allows Stored XSS. This issue affects Mediawiki - WikiSEO Extension: from * before 1.46.1, 1.45.5, 1.43.10.

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Meta Information

Published
2026-09-29
Last Modified
2026-09-29
Generated
2026-09-29
AI Q&A
2026-09-29
EPSS Evaluated
N/A
NVD
CVE-2026-100243
EUVD
EUVD-2026-89084

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
wikimedia_foundation mediawiki_wikiseo_extension to 1.46.1 (exc)
wikimedia_foundation mediawiki_wikiseo_extension 1.45.5
wikimedia_foundation mediawiki_wikiseo_extension 1.43.10
wikimedia_foundation mediawiki_wikiseo_extension From 1.43.10 (inc) to 1.46.1 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 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.

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Executive Summary

This is a Stored Cross-Site Scripting (XSS) vulnerability in the Wikimedia Foundation MediaWiki WikiSEO Extension. It allows attackers to inject malicious scripts into web pages that are then stored on the server and served to other users.

Detection Guidance

To detect this stored XSS vulnerability in the WikiSEO extension, inspect web application logs for unusual input patterns in WikiSEO-related fields. Check for JavaScript code snippets or HTML tags in stored content like meta tags or descriptions. Use browser developer tools to monitor network requests for suspicious payloads sent to the server.

Impact Analysis

If you use the affected WikiSEO Extension versions, attackers could steal your session cookies, redirect you to malicious sites, or perform actions on your behalf without your knowledge. This could lead to unauthorized access to your account or data.

Compliance Impact

This vulnerability could lead to data breaches, violating GDPR's data protection requirements and HIPAA's security rules. It may result in unauthorized access to personal or sensitive data, leading to legal penalties and reputational damage.

Mitigation Strategies

Immediately update the WikiSEO extension to version 1.46.1, 1.45.5, or 1.43.10 or later. Disable the extension if an update is not available. Implement input validation and output encoding for all user-supplied data in the extension. Review and sanitize existing stored content that may contain malicious scripts.

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