CVE-2021-37633 : Security Advisory and Response

Discourse, an open-source discussion platform, is susceptible to an XSS vulnerability via d-popover and d-html-popover attribute in versions prior to 2.7.8. This vulnerability impacts sites that have altered or disabled Content Security Policy.

Understanding CVE-2021-37633

This CVE identifies an XSS vulnerability in Discourse's rendering of d-popover tooltips.

What is CVE-2021-37633?

In versions before 2.7.8, Discourse is exposed to XSS attacks due to improper rendering of d-popover tooltips. The vulnerability is limited to sites with modified or disabled default Content Security Policy.

The Impact of CVE-2021-37633

With a CVSS base score of 7.4 (High Severity), this XSS vulnerability can lead to compromised confidentiality on affected Discourse instances.

Technical Details of CVE-2021-37633

This section covers the technical aspects of the CVE.

Vulnerability Description

The XSS vulnerability in Discourse stems from insecure rendering of d-popover tooltips, allowing malicious actors to execute scripts in the context of the website.

Affected Systems and Versions

Discourse versions earlier than 2.7.8 are vulnerable to this XSS exploit when Content Security Policy modifications weaken security measures.

Exploitation Mechanism

Attackers can exploit this vulnerability by injecting malicious scripts into d-popover tooltips, potentially compromising user data.

Mitigation and Prevention

Here's how you can secure your Discourse instance against CVE-2021-37633.

Immediate Steps to Take

Update Discourse to version 2.7.8 or later to patch the XSS vulnerability.
Ensure the Content Security Policy is enabled and correctly configured to prevent XSS attacks.

Long-Term Security Practices

Regularly monitor and apply security updates to Discourse to prevent future vulnerabilities.
Educate users on safe browsing practices to minimize the risk of XSS attacks.

Patching and Updates

Stay informed about security advisories and patches released by Discourse to protect your platform from emerging threats.