CVE-2021-27516 Explained : Impact and Mitigation

A vulnerability has been identified in URI.js (aka urijs) before version 1.19.6, where it mishandles certain uses of backslash, such as http:/ which leads to interpreting the URI as a relative path.

Understanding CVE-2021-27516

This vulnerability impacts the URI.js library before version 1.19.6, causing it to misinterpret specific uses of backslashes.

What is CVE-2021-27516?

CVE-2021-27516 is a vulnerability in URI.js (aka urijs) versions prior to 1.19.6. The issue arises from mishandling backslashes, resulting in the misinterpretation of URIs.

The Impact of CVE-2021-27516

Exploitation of this vulnerability could lead to security implications, as the URI might be processed incorrectly, potentially allowing attackers to manipulate or access unintended resources.

Technical Details of CVE-2021-27516

This section provides a deeper insight into the technical aspects of the CVE.

Vulnerability Description

The vulnerability arises due to URI.js mishandling specific uses of backslashes, like http:/, causing it to treat the URI as a relative path.

Affected Systems and Versions

All versions of URI.js prior to 1.19.6 are impacted by this vulnerability.

Exploitation Mechanism

By crafting a malicious URI with certain backslash patterns, an attacker can trick URI.js into misinterpreting the URI's structure.

Mitigation and Prevention

Protecting systems from CVE-2021-27516 requires immediate action and long-term security practices.

Immediate Steps to Take

Users are advised to update URI.js to version 1.19.6 or newer to mitigate the risk of exploitation.

Long-Term Security Practices

Implement secure coding practices, input validation mechanisms, and security reviews to prevent similar vulnerabilities in the future.

Patching and Updates

Regularly check for updates and patches for URI.js to address known security issues and strengthen the overall security posture.