CVE-2021-44855:Blind Stored XSS Vulnerability in MediaWiki Upload Image Feature

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Description Preview

CVE-2021-44855 affects MediaWiki versions before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. The vulnerability is a Blind Stored Cross-Site Scripting (XSS) issue that exists in the Upload Image feature. Attackers can exploit this vulnerability by crafting malicious URLs that, when processed by the Upload Image feature, can store XSS payloads that execute when viewed by other users.

Overview

This vulnerability (CWE-79: Cross-site Scripting) allows attackers to inject malicious client-side scripts into MediaWiki instances through specially crafted URLs targeting the Upload Image functionality. Since this is a blind stored XSS, the attacker may not immediately see the execution of their payload, but it remains persistent in the system and can execute when administrators or other users access affected pages. This could lead to session hijacking, credential theft, or other client-side attacks against MediaWiki users with elevated privileges.

Remediation

To address this vulnerability, administrators should update their MediaWiki installations to the following patched versions:

  • Version 1.35.5 or later if using the 1.35.x branch
  • Version 1.36.3 or later if using the 1.36.x branch
  • Version 1.37.1 or later if using the 1.37.x branch

If immediate updates are not possible, consider implementing additional security controls such as:

  • Restricting upload permissions to trusted users only
  • Implementing Content Security Policy (CSP) headers to mitigate XSS attacks
  • Regularly monitoring upload logs for suspicious activity

References

  1. Wikimedia Phabricator Issue Tracker: https://phabricator.wikimedia.org/T293589
  2. Gentoo Linux Security Advisory: https://security.gentoo.org/glsa/202305-24
  3. CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Industry ExposureMost to least
This section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.

  1. Manufacturing
    Manufacturing
  2. Professional, Scientific, & Technical Services
    Professional, Scientific, & Technical Services
  3. Public Administration
    Public Administration
  4. Accommodation & Food Services
    Accommodation & Food Services
  5. Administrative, Support, Waste Management & Remediation Services
    Administrative, Support, Waste Management & Remediation Services
  6. Agriculture, Forestry Fishing & Hunting
    Agriculture, Forestry Fishing & Hunting
  7. Arts, Entertainment & Recreation
    Arts, Entertainment & Recreation
  8. Construction
    Construction
  9. Educational Services
    Educational Services
  10. Finance and Insurance
    Finance and Insurance
  11. Health Care & Social Assistance
    Health Care & Social Assistance
  12. Information
    Information
  13. Management of Companies & Enterprises
    Management of Companies & Enterprises
  14. Mining
    Mining
  15. Other Services (except Public Administration)
    Other Services (except Public Administration)
  16. Real Estate Rental & Leasing
    Real Estate Rental & Leasing
  17. Retail Trade
    Retail Trade
  18. Transportation & Warehousing
    Transportation & Warehousing
  19. Utilities
    Utilities
  20. Wholesale Trade
    Wholesale Trade

Focus on What Matters

  1. See Everything.
  2. Identify True Risk.
  3. Proactively Mitigate Threats.

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Armis Vulnerability Intelligence Database