CVE-2024-10491 in express
Summary
by MITRE • 10/29/2024
A vulnerability has been identified in the Express response.links function, allowing for arbitrary resource injection in the Link header when unsanitized data is used.
The issue arises from improper sanitization in `Link` header values, which can allow a combination of characters like `,`, `;`, and `<>` to preload malicious resources.
This vulnerability is especially relevant for dynamic parameters.
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Analysis
by VulDB Data Team • 01/30/2026
The vulnerability identified as CVE-2024-10491 represents a critical security flaw within the Express response.links function that enables arbitrary resource injection in HTTP Link headers. This issue stems from inadequate input sanitization mechanisms that fail to properly validate and escape special characters commonly found in HTTP header values. The vulnerability specifically manifests when unsanitized data is passed through the response.links function, creating potential attack vectors for malicious actors to manipulate HTTP responses and influence client-side resource loading behavior.
The technical exploitation of this vulnerability relies on the improper handling of characters including commas, semicolons, and angle brackets which are fundamental components of HTTP Link headers. When these characters are not properly sanitized, attackers can inject malicious resource references that get processed by client browsers or intermediary systems. The vulnerability becomes particularly dangerous in dynamic parameter scenarios where user input flows directly into the response.links function without adequate validation or encoding. This creates a pathway for attackers to preload malicious resources, potentially leading to cross-site scripting attacks, resource exhaustion, or other client-side exploitation techniques.
From an operational perspective, this vulnerability poses significant risks to web applications utilizing Express.js frameworks, particularly those that dynamically generate Link headers based on user input or external data sources. The impact extends beyond simple data corruption as it can enable attackers to manipulate browser behavior, potentially leading to unauthorized resource loading, performance degradation, or even complete application compromise. The vulnerability's relevance to dynamic parameters amplifies its danger since it can be exploited through various input vectors including API endpoints, form submissions, or URL parameters that are processed through the affected function.
Security mitigations for CVE-2024-10491 should prioritize input validation and sanitization at multiple layers within the application architecture. Developers must implement comprehensive character filtering and encoding mechanisms specifically for Link header values, ensuring that special characters are properly escaped or removed before being passed to the response.links function. The implementation should follow established security practices such as those outlined in CWE-116 for proper encoding of special characters and CWE-79 for preventing cross-site scripting vulnerabilities. Additionally, organizations should consider implementing automated security scanning tools that can detect improper header handling patterns and enforce secure coding practices through static analysis and runtime monitoring systems.
The vulnerability aligns with ATT&CK technique T1071.004 which covers application layer protocol manipulation, specifically targeting HTTP headers for malicious purposes. This categorization emphasizes the network protocol-level nature of the attack vector and the need for comprehensive header validation across all application layers. Security teams should also consider implementing Content Security Policy headers and other protective measures to mitigate the broader impact of potential exploitation, while ensuring that the fix does not introduce regressions in legitimate functionality that depends on proper Link header generation. The remediation process requires careful testing to validate that all dynamic parameter handling within the Express framework properly sanitizes input data before header generation occurs.