CVE-2018-1999024 in MathJax
Summary
by MITRE
MathJax version prior to version 2.7.4 contains a Cross Site Scripting (XSS) vulnerability in the \unicode{} macro that can result in Potentially untrusted Javascript running within a web browser. This attack appear to be exploitable via The victim must view a page where untrusted content is processed using Mathjax. This vulnerability appears to have been fixed in 2.7.4 and later.
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Analysis
by VulDB Data Team • 04/25/2023
The vulnerability identified as CVE-2018-1999024 represents a critical cross site scripting flaw within the MathJax mathematical typesetting library, specifically affecting versions prior to 2.7.4. This vulnerability resides within the \unicode{} macro implementation, which processes Unicode characters for mathematical rendering. The flaw allows malicious actors to inject arbitrary JavaScript code that executes within the context of a victim's browser when processing web pages containing untrusted mathematical content. The attack vector requires user interaction through viewing a webpage that utilizes MathJax to render mathematical expressions, making it particularly concerning for web applications that process user-generated mathematical content or display third-party mathematical formulas.
The technical nature of this vulnerability stems from insufficient input validation and sanitization within the Unicode macro processing functionality of MathJax. When the \unicode{} macro encounters specially crafted input, it fails to properly escape or filter potentially malicious content, creating an avenue for code injection. This represents a classic XSS vulnerability classified under CWE-79, which specifically addresses cross-site scripting flaws where untrusted data is incorporated into web pages without proper validation or escaping mechanisms. The vulnerability demonstrates how mathematical rendering libraries can become attack surfaces when they process untrusted input without adequate security controls, particularly when dealing with Unicode character sequences that may contain embedded script tags or other malicious payloads.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to perform a wide range of malicious activities including session hijacking, credential theft, data exfiltration, and manipulation of web page content. Users who view compromised web pages containing malicious mathematical expressions become unwitting participants in the attack, as the vulnerability operates entirely within their browser context without requiring any additional user interaction beyond normal page viewing. This makes the vulnerability particularly dangerous in environments where users frequently encounter mathematical content from untrusted sources, such as academic platforms, wikis, forums, or content management systems that support mathematical notation. The exploitation requires no special privileges or complex attack chains, making it accessible to threat actors with minimal technical expertise.
Mitigation strategies for CVE-2018-1999024 primarily focus on updating to MathJax version 2.7.4 or later, which includes proper input validation and sanitization for the \unicode{} macro. Organizations should implement comprehensive patch management processes to ensure all instances of MathJax are updated promptly, particularly in environments where user-generated content is processed. Additional defensive measures include implementing content security policies that restrict script execution, employing web application firewalls to monitor for suspicious mathematical content patterns, and conducting regular security assessments of web applications that utilize MathJax. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving code injection and malicious content delivery, specifically T1059.007 for scripting and T1566 for malicious content delivery, making it a significant concern for organizations implementing security controls against these attack patterns. The vulnerability serves as a reminder of the importance of securing all components within web applications, including mathematical rendering libraries that may not be considered primary security concerns but can provide critical attack vectors.