CVE-2021-22959 : Exploit Details and Defense Strategies

A critical CVE-2021-22959 related to HTTP Request Smuggling in llhttp has been identified and published by HackerOne.

Understanding CVE-2021-22959

This CVE involves a vulnerability in the parser of llhttp leading to HTTP Request Smuggling (HRS) in versions prior to llhttp v2.1.4 and v6.0.6.

What is CVE-2021-22959?

The parser in llhttp improperly accepts requests with a space right after the header name before the colon, enabling potential HTTP Request Smuggling attacks.

The Impact of CVE-2021-22959

The vulnerability can be exploited by attackers to perform HTTP Request Smuggling attacks, potentially leading to sensitive data exposure or unauthorized access.

Technical Details of CVE-2021-22959

This section outlines critical technical details regarding the CVE.

Vulnerability Description

The flaw in llhttp allows requests with a space right after the header name before the colon, facilitating HTTP Request Smuggling.

Affected Systems and Versions

llhttp versions earlier than v2.1.4 and v6.0.6 are affected by this vulnerability.

Exploitation Mechanism

Attackers can exploit this flaw by sending crafted requests with a space after the header name, enabling HTTP Request Smuggling.

Mitigation and Prevention

It is crucial to understand the mitigation strategies to protect systems from CVE-2021-22959.

Immediate Steps to Take

Apply patches provided by llhttp promptly to fix the vulnerability and prevent potential exploitation.

Long-Term Security Practices

Implement secure coding practices and regular security audits to prevent similar vulnerabilities in the future.

Patching and Updates

Regularly update llhttp to versions v2.1.4 and v6.0.6 or later to ensure protection against HTTP Request Smuggling attacks.