CVE-2025-61682 in Semantic MediaWiki
Summary
by MITRE • 09/18/2026
Semantic MediaWiki is a free, open-source extension to MediaWiki that lets users store and query data within the wiki's pages. Versions starting in 3.1.0 and prior to 7.0.0 insert the unsanitized value of a data attribute into the DOM as HTML, allowing for stored XSS through wikitext. Version 7.0.0 patches the issue.
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Analysis
by VulDB Data Team • 09/18/2026
Semantic MediaWiki is an open-source extension designed to enhance the standard MediaWiki platform by enabling users to store structured data and perform complex queries directly within wiki pages. This functionality transforms static content into a dynamic database, allowing for sophisticated information retrieval and presentation. However, in versions ranging from 3.1.0 up to but not including version 7.0.0, a critical security flaw exists that undermines the integrity of this structured data environment. The vulnerability stems from improper input validation within the rendering engine responsible for processing wiki markup into HTML output. Specifically, when certain attributes are processed, the system fails to adequately sanitize user-supplied values before injecting them into the Document Object Model as raw HTML elements.
The technical core of this flaw lies in the handling of data attributes during the conversion process from wikitext to rendered web content. When a user inputs specific markup that includes custom properties or metadata fields, the application directly embeds these unsanitized strings into the DOM structure without applying necessary encoding or escaping mechanisms. This oversight allows an attacker who has write access to wiki pages to inject malicious JavaScript code disguised as legitimate data attributes. Because the browser interprets this injected content as executable script rather than plain text, it executes within the context of the victim's session whenever they view the compromised page.
This vulnerability is classified under CWE-79, which denotes Improper Neutralization of Input During Web Page Generation commonly known as Cross-Site Scripting or XSS. More specifically, because the malicious payload is stored on the server and served to multiple users over time, it falls into the category of Stored XSS rather than Reflected XSS. The attack vector leverages the trusted nature of the wiki platform; victims trust content originating from Semantic MediaWiki pages, making them susceptible to exploitation without realizing they are interacting with hostile code. This aligns with MITRE ATT&CK technique T1059.007, which covers JavaScript execution within web browsers, and potentially T1189 if used for initial access or persistence depending on the attacker's goals.
The operational impact of this vulnerability is significant due to its potential for widespread exploitation across any wiki instance running an affected version. An authenticated user with editing privileges can plant a payload that affects all subsequent viewers, including administrators who may have higher privilege levels and sensitive data access. Successful exploitation could lead to session hijacking through cookie theft, allowing attackers to impersonate legitimate users and escalate their privileges within the application. Furthermore, it enables phishing attacks where victims are redirected to malicious sites or prompted for credentials on fake login pages embedded via DOM manipulation. In severe cases, this can facilitate keylogging or unauthorized modification of wiki content, compromising the confidentiality, integrity, and availability of the information system.
Mitigation strategies must prioritize immediate software updates as the primary defense vector. Organizations running Semantic MediaWiki should upgrade to version 7.0.0 or later, where developers have implemented robust input validation and output encoding practices that neutralize this specific injection path. For environments where upgrading is not immediately feasible due to compatibility constraints with other extensions or custom code, temporary mitigations include implementing strict Content Security Policy headers to restrict script execution sources and disabling the ability for untrusted users to edit pages containing structured data attributes. Additionally, deploying a Web Application Firewall can help detect and block requests attempting to inject known XSS payloads into wiki markup fields, providing an additional layer of defense while permanent remediation is pursued.