CVE-2023-22468 in Discourse
Summary
by MITRE • 01/26/2023
Discourse is an open source platform for community discussion. Versions prior to 2.8.13 (stable), 3.0.0.beta16 (beta) and 3.0.0beta16 (tests-passed), are vulnerable to cross-site Scripting. A maliciously crafted URL can be included in a post to carry out cross-site scripting attacks on sites with disabled or overly permissive CSP (Content Security Policy). Discourse's default CSP prevents this vulnerability. This vulnerability is patched in versions 2.8.13 (stable), 3.0.0.beta16 (beta) and 3.0.0beta16 (tests-passed). As a workaround, enable and/or restore your site's CSP to the default one provided with Discourse.
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Analysis
by VulDB Data Team • 02/20/2023
CVE-2023-22468 represents a cross-site scripting vulnerability affecting Discourse community discussion platforms prior to specific version releases. This vulnerability stems from improper input validation and sanitization of user-generated content, particularly when processing URLs within posts. The flaw allows attackers to inject malicious scripts through carefully crafted URLs that can execute in the context of other users' browsers when they view affected content. The vulnerability specifically targets environments where Content Security Policy mechanisms are either disabled or configured with overly permissive rules, creating an attack surface that would otherwise be protected. This weakness aligns with CWE-79 which categorizes cross-site scripting vulnerabilities as improper neutralization of input during web page generation, making it a critical concern for web application security.
The technical exploitation of this vulnerability occurs when a malicious user creates a post containing a specially crafted URL that, when rendered by other users' browsers, triggers script execution. The vulnerability is particularly dangerous because it leverages the trust relationship between users and the platform, allowing attackers to execute arbitrary JavaScript code in the context of legitimate user sessions. Without proper Content Security Policy enforcement, these scripts can access session cookies, perform actions on behalf of users, steal sensitive information, or redirect users to malicious sites. The default CSP configuration in Discourse provides adequate protection by restricting script execution and controlling resource loading, but when this protection is disabled or weakened, the vulnerability becomes exploitable. This scenario demonstrates how security controls can be bypassed through improper configuration rather than inherent flaws in the application code itself.
The operational impact of CVE-2023-22468 extends beyond simple script execution to potentially compromise entire user sessions and platform integrity. Attackers could leverage this vulnerability to perform session hijacking, steal user credentials, manipulate forum content, or conduct phishing attacks against community members. The vulnerability affects the core functionality of community platforms where user-generated content is central to the experience, potentially leading to widespread compromise across user bases. Organizations relying on Discourse for sensitive discussions or community management face significant risk if their CSP policies are not properly configured. The vulnerability's exploitation requires minimal technical skill and can be automated, making it particularly dangerous for platforms with large user bases where content moderation is challenging. This type of vulnerability directly impacts the confidentiality, integrity, and availability of community platforms, potentially leading to reputational damage and regulatory compliance issues.
Mitigation strategies for CVE-2023-22468 focus on both immediate remediation and long-term security hardening. The primary solution involves upgrading to patched versions 2.8.13 (stable), 3.0.0.beta16 (beta), or 3.0.0beta16 (tests-passed) where the vulnerability has been addressed through proper input sanitization and URL handling. Organizations should immediately restore default Content Security Policy configurations that provide robust protection against script injection attacks. Additional mitigations include implementing comprehensive input validation for all user-generated content, particularly URLs and links, and establishing regular security audits of platform configurations. The vulnerability highlights the importance of defense-in-depth strategies where multiple security controls work together to prevent exploitation. Security teams should also implement monitoring for suspicious content patterns and maintain regular updates to ensure all platform components remain protected against similar vulnerabilities. This case exemplifies how proper security configuration and timely patch management are essential for maintaining platform integrity and user trust in community-driven applications.