CVE-2020-6816 Explained : Impact and Mitigation

In Mozilla Bleach before 3.12, a mutation XSS vulnerability exists in bleach.clean when certain tags are whitelisted.

Understanding CVE-2020-6816

In this CVE, a specific vulnerability in Mozilla Bleach is detailed, highlighting the potential risks and impact.

What is CVE-2020-6816?

The CVE-2020-6816 vulnerability involves a mutation XSS issue in Mozilla Bleach before version 3.12. This vulnerability occurs when certain tags are whitelisted in the bleach.clean function.

The Impact of CVE-2020-6816

The vulnerability can be exploited by attackers to execute malicious scripts within the context of a user's browser, potentially leading to sensitive data exposure or unauthorized actions.

Technical Details of CVE-2020-6816

This section delves into the technical aspects of the CVE, providing insights into the vulnerability and its implications.

Vulnerability Description

The vulnerability in Mozilla Bleach before 3.12 allows for mutation XSS when specific tags are whitelisted in the bleach.clean function.

Affected Systems and Versions

Product: Mozilla Bleach
Versions Affected: <=3.11

Exploitation Mechanism

The vulnerability can be exploited by crafting malicious input containing RCDATA, svg, or math tags that are whitelisted, along with the strip=False keyword argument.

Mitigation and Prevention

In this section, we explore the steps to mitigate the risks associated with CVE-2020-6816.

Immediate Steps to Take

Update Mozilla Bleach to version 3.12 or newer to patch the vulnerability.
Avoid processing untrusted user input that includes the vulnerable tags mentioned in the exploit.

Long-Term Security Practices

Regularly update software and libraries to ensure the latest security patches are applied.
Implement input validation and output encoding to prevent XSS attacks.

Patching and Updates

Stay informed about security advisories and updates from Mozilla to address vulnerabilities promptly.