CVE-2024-54142: XSS in Discourse AI Plugin

An attacker could leverage this XSS vulnerability to inject arbitrary JavaScript code into Discourse posts. This could lead to various malicious outcomes, including stealing user cookies, redirecting users to phishing sites, or defacing the website. The impact is particularly severe because the vulnerability arises from a seemingly innocuous feature – sharing AI Bot conversations. Successful exploitation could compromise user accounts and the integrity of the Discourse platform. The blast radius extends to all users who view posts containing oneboxed AI Bot conversations with malicious HTML entities.

1. Reserved2024-11-29
2. Published2025-01-14
3. Modified2025-01-15
4. EPSS updated2026-04-02

The primary mitigation is to upgrade the Discourse AI plugin to version 92f122c or later, which contains the fix. If upgrading is not immediately feasible, a temporary workaround is to remove all groups from the 'ai bot public sharing allowed groups' site setting. This will prevent the sharing of AI Bot conversations, effectively disabling the vulnerable feature. Monitor Discourse logs for any unusual activity or suspicious JavaScript execution. After upgrading, confirm the fix by attempting to share a conversation containing HTML entities and verifying that the entities are properly sanitized and do not execute as JavaScript.