CVE-2019-20056 Explained : Impact and Mitigation

A problem has been identified in the stb_image.h file, also known as the stb image loader, version 2.23. This issue affects various products, including libsixel. The specific problem occurs in the stbi__shiftsigned function, where an assertion failure takes place.

Understanding CVE-2019-20056

This CVE involves an assertion failure in the stbi__shiftsigned function within the stb_image.h file, affecting version 2.23 and products like libsixel.

What is CVE-2019-20056?

stb_image.h (stb image loader) 2.23 has an assertion failure in stbi__shiftsigned, impacting libsixel and other products.

The Impact of CVE-2019-20056

The vulnerability can lead to a denial of service (DoS) condition or potentially allow attackers to execute arbitrary code.

Technical Details of CVE-2019-20056

This section provides more technical insights into the CVE.

Vulnerability Description

The issue arises from an assertion failure in the stbi__shiftsigned function of stb_image.h version 2.23.

Affected Systems and Versions

stb_image.h version 2.23
Products using the stb image loader, such as libsixel

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting a malicious image file that triggers the assertion failure in the stbi__shiftsigned function.

Mitigation and Prevention

Protecting systems from CVE-2019-20056 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply vendor patches or updates to address the vulnerability.
Consider implementing file type validation to prevent malicious image uploads.

Long-Term Security Practices

Regularly update software and libraries to the latest versions.
Conduct security assessments and code reviews to identify and mitigate similar vulnerabilities.

Patching and Updates

Check for patches or updates from the stb image loader or affected product vendors to fix the assertion failure in stbi__shiftsigned.