CVE-2023-43658 : Security Advisory and Response

This article provides detailed information about CVE-2023-43658, focusing on the improper escaping of user input in discourse-calendar plugin for the Discourse messaging platform.

Understanding CVE-2023-43658

CVE-2023-43658 relates to a vulnerability in the discourse-calendar plugin that could lead to Cross-Site Scripting (XSS) due to improper escaping of user input.

What is CVE-2023-43658?

The vulnerability in discourse-calendar arises from improper neutralization of input during web page generation, specifically affecting the 'email preview' UI when a site has Content Security Policy (CSP) disabled.

The Impact of CVE-2023-43658

The impact of this vulnerability is rated as HIGH, with significant confidentiality, integrity, and availability impacts when exploited. Users are required to have interactions to trigger the attack.

Technical Details of CVE-2023-43658

The vulnerability is assigned a CVSSv3.1 base score of 8, indicating a high severity issue with low attack complexity and network access required. The affected user's privileges are low, and the scope remains unchanged.

Vulnerability Description

The vulnerability in discourse-calendar is caused by the incorrect handling of user input, leading to potential XSS attacks, especially when CSP is disabled.

Affected Systems and Versions

Users using versions of the discourse-calendar plugin before <97883109 are affected by this vulnerability, requiring immediate action to secure their systems.

Exploitation Mechanism

Exploiting this vulnerability involves injecting malicious scripts into event titles within the 'email preview' UI, taking advantage of the lack of proper input validation.

Mitigation and Prevention

To mitigate the risks associated with CVE-2023-43658, immediate steps and long-term security practices need to be implemented.

Immediate Steps to Take

Users are strongly advised to upgrade to the latest version of the discourse-calendar plugin, where the vulnerability has been resolved. Alternatively, enabling CSP on the forum can help protect against potential XSS attacks.

Long-Term Security Practices

It is recommended to regularly update software components and maintain a robust security posture by following best practices to prevent similar vulnerabilities in the future.

Patching and Updates

Regularly check for security updates and patches released by Discourse to ensure that your systems are protected from known security issues.