CVE-2022-28204 in MediaWiki
Summary
by MITRE • 09/20/2022
A denial-of-service issue was discovered in MediaWiki 1.37.x before 1.37.2. Rendering of w/index.php?title=Special%3AWhatLinksHere&target=Property%3AP31&namespace=1&invert=1 can take more than thirty seconds. There is a DDoS risk.
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Analysis
by VulDB Data Team • 05/29/2025
This vulnerability exists within MediaWiki version 1.37.x prior to 1.37.2 and represents a significant denial-of-service condition that can be exploited to cause system degradation or complete unavailability. The issue manifests specifically when processing requests to the Special:WhatLinksHere page with particular parameters including a target property, namespace filtering, and inversion flags. The affected endpoint demonstrates severe performance degradation where rendering times exceed thirty seconds, creating a substantial operational risk that can be amplified into a distributed denial-of-service condition. This vulnerability directly impacts the core functionality of MediaWiki's special pages and represents a critical weakness in the application's request handling and resource allocation mechanisms.
The technical flaw stems from inefficient query processing and database operations within the Special:WhatLinksHere functionality when dealing with complex parameter combinations. When users access the specific URL pattern with Property:P31 as target, namespace 1 filtering, and inversion enabled, the system initiates resource-intensive operations that fail to scale appropriately. The underlying issue involves inadequate query optimization and missing performance safeguards that allow malicious actors to construct requests that consume excessive computational resources. This behavior aligns with CWE-400 vulnerability classification related to excessive resource consumption and represents a classic example of a denial-of-service attack vector that exploits application logic flaws rather than network-level weaknesses.
The operational impact of this vulnerability extends beyond simple performance degradation to create real security concerns for MediaWiki deployments. Organizations running affected versions face significant risk of service disruption, particularly when subjected to coordinated attacks or automated exploitation attempts. The thirty-second rendering time threshold indicates that the system becomes effectively unresponsive to legitimate user requests during the vulnerable period, creating a window where normal operations are severely impacted. This vulnerability particularly affects collaborative environments where MediaWiki serves as a central knowledge management platform, as the service disruption can halt productivity and information sharing across entire organizations. The DDoS risk component means that even a single malicious actor can potentially disrupt service for all users, making this a critical concern for public-facing wikis.
Mitigation strategies should focus on immediate patching to version 1.37.2 or later, which contains the necessary fixes for the query optimization issues. Organizations should implement rate limiting and request monitoring to detect and prevent exploitation attempts targeting the vulnerable endpoint. Network-level protections including firewall rules and load balancer configurations can help reduce the impact of automated attacks by limiting the number of requests that can be processed from individual sources. Additionally, administrators should consider implementing database query timeouts and resource allocation limits to prevent any single request from consuming excessive system resources. The fix implemented in the patched version addresses the root cause by optimizing the database queries and adding appropriate performance checks that prevent the exponential resource consumption pattern that enabled the vulnerability. This vulnerability demonstrates the importance of proper input validation and query optimization in web applications, particularly in content management systems that handle complex data relationships and cross-references.