CVE-2019-20445 : What You Need to Know

Netty version 4.1.44 and prior versions contain a vulnerability in the HttpObjectDecoder.java file allowing multiple Content-Length headers or a Transfer-Encoding header alongside a Content-Length header.

Understanding CVE-2019-20445

Netty versions prior to 4.1.44 are susceptible to a security flaw that can be exploited through specific HTTP header configurations.

What is CVE-2019-20445?

This CVE pertains to a vulnerability in Netty versions before 4.1.44 that allows the presence of multiple Content-Length headers or a Transfer-Encoding header alongside a Content-Length header, potentially leading to security breaches.

The Impact of CVE-2019-20445

The vulnerability in Netty versions before 4.1.44 could be exploited by malicious actors to manipulate HTTP headers, potentially causing security risks such as data leakage or denial of service.

Technical Details of CVE-2019-20445

Netty version 4.1.44 and earlier versions are affected by a specific vulnerability related to HTTP header processing.

Vulnerability Description

The HttpObjectDecoder.java file in Netty versions before 4.1.44 allows the presence of multiple Content-Length headers or a Transfer-Encoding header alongside a Content-Length header.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions: Netty versions before 4.1.44

Exploitation Mechanism

The vulnerability can be exploited by sending crafted HTTP requests containing multiple Content-Length headers or a combination of Transfer-Encoding and Content-Length headers.

Mitigation and Prevention

To address CVE-2019-20445, immediate actions and long-term security practices are recommended.

Immediate Steps to Take

Update Netty to version 4.1.44 or later to mitigate the vulnerability.
Monitor and analyze HTTP headers for any anomalies or irregularities.

Long-Term Security Practices

Regularly update software components and libraries to the latest secure versions.
Implement strict HTTP header validation mechanisms to prevent header manipulation attacks.

Patching and Updates

Stay informed about security advisories and patches released by Netty and related vendors.
Apply security patches promptly to ensure protection against known vulnerabilities.