CVE-2013-7451 in Node.js
Summary
by MITRE
The validator module before 1.1.0 for Node.js allows remote attackers to bypass the XSS filter via a nested tag.
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Analysis
by VulDB Data Team • 05/14/2026
The vulnerability identified as CVE-2013-7451 affects the validator module for Node.js, specifically versions prior to 1.1.0, presenting a critical security flaw that enables remote attackers to circumvent cross-site scripting protection mechanisms. This issue resides within the input validation and sanitization functionality that is fundamental to web application security, particularly when handling user-supplied data that may contain malicious script content. The vulnerability demonstrates a failure in the module's ability to properly identify and neutralize potentially harmful HTML constructs, creating a pathway for attackers to inject malicious code that can execute within the context of other users' browsers.
The technical flaw stems from insufficient parsing and validation logic within the validator module's XSS filtering implementation. When processing nested HTML tags, the module fails to adequately traverse and sanitize the hierarchical structure of the input, allowing attackers to craft malicious payloads that exploit this parsing gap. The vulnerability specifically manifests when nested tags are present in the input data, where the filter does not recursively examine or properly neutralize the nested elements. This behavior aligns with CWE-79, which describes cross-site scripting vulnerabilities arising from inadequate input validation and sanitization, particularly when dealing with complex HTML structures. The flaw essentially allows attackers to bypass the intended security controls by constructing payloads that exploit the module's limited understanding of nested tag relationships.
The operational impact of this vulnerability is severe, as it directly undermines the security posture of Node.js applications that rely on the validator module for input sanitization. Attackers can leverage this weakness to inject malicious JavaScript code into web applications, potentially leading to session hijacking, data theft, or unauthorized actions performed on behalf of authenticated users. The remote nature of the attack means that malicious actors do not require local system access or special privileges to exploit the vulnerability, making it particularly dangerous in web-facing applications. This weakness can be exploited across various attack vectors including form submissions, URL parameters, and API endpoints where user input is processed through the vulnerable validator module.
Mitigation strategies for CVE-2013-7451 primarily focus on upgrading to version 1.1.0 or later of the validator module, which includes enhanced parsing logic and improved handling of nested HTML structures. Organizations should conduct comprehensive vulnerability assessments to identify all applications and services utilizing the vulnerable module, implementing immediate patching procedures across their infrastructure. Additionally, implementing multiple layers of defense-in-depth measures including web application firewalls, additional input validation at multiple points in the application architecture, and regular security code reviews can help reduce the risk of exploitation. The remediation efforts should also include monitoring for potential exploitation attempts and establishing incident response procedures to address any successful attacks that may occur despite defensive measures. This vulnerability serves as a reminder of the critical importance of thorough input validation and the potential consequences of inadequate parsing logic in security-critical components, particularly when considering the ATT&CK framework's approach to command and control operations and persistence mechanisms that can leverage such XSS vulnerabilities for further compromise.