CVE-2020-26137 : Vulnerability Insights and Analysis

CVE-2020-26137 is a vulnerability in urllib3 before version 1.25.9 that allows CRLF injection if the attacker controls the HTTP request method by inserting CR and LF control characters in the first argument of putrequest(). This vulnerability is similar to CVE-2020-26116.

Understanding CVE-2020-26137

urllib3 before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest().

What is CVE-2020-26137?

CVE-2020-26137 is a security vulnerability in urllib3 that can be exploited by an attacker to perform CRLF injection if they control the HTTP request method.

The Impact of CVE-2020-26137

This vulnerability can be exploited to manipulate HTTP headers, potentially leading to various attacks such as HTTP request smuggling.

Technical Details of CVE-2020-26137

urllib3 before version 1.25.9 is affected by this vulnerability.

Vulnerability Description

The issue arises from improper handling of CR and LF characters in the HTTP request method.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions: All versions before 1.25.9 are affected.

Exploitation Mechanism

Attackers can exploit this vulnerability by inserting CR and LF control characters in the first argument of putrequest() when controlling the HTTP request method.

Mitigation and Prevention

It is crucial to take immediate steps to mitigate the risks posed by CVE-2020-26137.

Immediate Steps to Take

Update urllib3 to version 1.25.9 or later to patch the vulnerability.
Monitor for any unusual HTTP header manipulation.

Long-Term Security Practices

Regularly update libraries and dependencies to their latest secure versions.
Implement secure coding practices to prevent CRLF injection vulnerabilities.

Patching and Updates

Ensure that all systems using urllib3 are updated to version 1.25.9 or above to address the CVE-2020-26137 vulnerability.