CVE-2019-15124 in MobileFrontend Extension
Summary
by MITRE
In the MobileFrontend extension for MediaWiki, XSS exists within the edit summary field of the watchlist feed. This affects REL1_31, REL1_32, and REL1_33.
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Analysis
by VulDB Data Team • 05/11/2025
The vulnerability CVE-2019-15124 represents a cross-site scripting weakness in the MobileFrontend extension for MediaWiki platforms, specifically affecting versions REL1_31 through REL1_33. This issue resides within the watchlist feed functionality where edit summaries are processed and displayed, creating a vector for malicious code injection. The vulnerability stems from insufficient input sanitization and output encoding mechanisms that fail to properly handle user-provided content within the edit summary field. Attackers can exploit this flaw by crafting malicious payloads in edit summaries that get executed when other users view the watchlist feed, potentially leading to unauthorized actions or data theft. The vulnerability operates under CWE-79 which classifies it as a cross-site scripting flaw, making it particularly dangerous in collaborative environments where multiple users interact with shared content. This weakness aligns with ATT&CK technique T1203 which involves exploiting web applications to gain access to user sessions and execute malicious scripts in the context of the victim's browser. The impact is significant as it allows attackers to perform actions such as stealing session cookies, redirecting users to malicious sites, or injecting malicious scripts that can compromise the entire user environment.
The technical implementation of this vulnerability occurs when the MobileFrontend extension processes edit summaries for display in the watchlist feed without proper sanitization of special characters or script tags. When a user submits an edit summary containing malicious JavaScript code, the system fails to encode or filter the input before rendering it in the HTML context of the watchlist. This creates a persistent XSS vector where any user viewing the affected watchlist feed becomes vulnerable to script execution. The vulnerability is particularly insidious because it leverages legitimate user interactions with the platform's watchlist functionality, making it difficult to distinguish between benign and malicious activity. The flaw exists in the rendering pipeline where user-generated content flows directly into HTML output without appropriate security controls, violating fundamental web security principles. The affected versions suggest this was a widespread issue across multiple release branches, indicating a systemic problem in the extension's input handling rather than a localized bug.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to establish persistent access to user accounts and compromise the integrity of collaborative editing environments. When exploited, the vulnerability allows attackers to steal session tokens, redirect users to phishing sites, or inject malicious content that can propagate through the watchlist system to multiple users. The affected MediaWiki installations become potential entry points for more sophisticated attacks, as compromised user sessions can be leveraged to access restricted content, modify wiki pages, or escalate privileges within the platform. Organizations using MediaWiki with MobileFrontend extensions face significant risk of data compromise and unauthorized access, particularly in environments where multiple users contribute to shared knowledge bases. The vulnerability's persistence in multiple release versions indicates that it was not properly addressed in security patches, creating extended exposure windows for organizations that have not yet upgraded to fixed versions. Security teams must consider the potential for this vulnerability to be used as a stepping stone for broader attacks against wiki infrastructure and user credentials.
Mitigation strategies for CVE-2019-15124 should focus on immediate input sanitization and output encoding improvements within the MobileFrontend extension. Organizations should implement proper HTML escaping and content security policy headers to prevent script execution in user-generated content areas. The recommended approach includes upgrading to patched versions of MediaWiki that address this vulnerability, as well as implementing additional security controls such as input validation filters that reject potentially dangerous characters and patterns. Security teams should also consider implementing web application firewalls to detect and block malicious payloads targeting this specific vulnerability. Regular security audits of MediaWiki extensions and core functionality should be conducted to identify similar input handling issues that could create similar attack vectors. Organizations should establish monitoring procedures to detect unusual activity in watchlist feeds and implement user education programs to raise awareness about the risks of submitting untrusted content in edit summaries. The remediation process must also include thorough testing of the patched solutions to ensure that legitimate functionality remains intact while eliminating the XSS vulnerability. Additionally, implementing automated security scanning tools that can detect similar vulnerabilities in other MediaWiki extensions will help prevent future incidents of this nature.