CVE-2021-39199 : Exploit Details and Defense Strategies

This CVE article provides an in-depth analysis of the cross-site scripting vulnerability found in remark-html.

Understanding CVE-2021-39199

CVE-2021-39199, also known as 'Cross site scripting via unsafe defaults in remark-html,' poses a critical risk to systems using affected versions.

What is CVE-2021-39199?

In affected versions of remark-html, user input was not sanitized, allowing arbitrary HTML to pass through, creating a potential for XSS attacks.

The Impact of CVE-2021-39199

The vulnerability has a CVSSv3.1 base score of 10 (Critical) with high confidentiality and integrity impact. The attack complexity is low, requiring no user interaction.

Technical Details of CVE-2021-39199

A detailed look at the technical aspects of the vulnerability.

Vulnerability Description

remark-html's affected versions did not sanitize user input, enabling XSS attacks.

Affected Systems and Versions

Products: remark-html
Vendor: remarkjs
Affected Versions: >= 14.0.0, < 14.0.1 and < 13.0.2

Exploitation Mechanism

User input not being sanitized in remark-html allowed for arbitrary HTML input, leading to potential XSS threats.

Mitigation and Prevention

Explore the steps to mitigate and prevent potential risks.

Immediate Steps to Take

Update remark-html to versions 13.0.2 and 14.0.1 to patch the vulnerability.
For older versions, implement

sanitize: true

if updating is not possible.

Long-Term Security Practices

Sanitize all user inputs in web applications to prevent XSS vulnerabilities.

Patching and Updates

Regularly check for security patches and updates for all dependencies used in your projects.