CVE-2024-49038: XSS in Microsoft Copilot Studio

The improper neutralization of input during web page generation is the root cause of this XSS vulnerability. An attacker could craft a malicious payload and inject it into a Copilot Studio web page. When a user views this page, the injected script executes within their browser context, allowing the attacker to steal cookies, session tokens, or redirect the user to a malicious website. Given the potential for privilege escalation over a network, this vulnerability could enable an attacker to compromise other systems accessible to the affected user, significantly expanding the attack surface. The impact is particularly severe in environments where Copilot Studio is integrated with sensitive data or critical business processes.

1. Reserved2024-10-11
2. Published2024-11-26
3. Modified2025-07-08
4. EPSS updated2026-04-02

Due to the lack of a specified fixed version, immediate mitigation strategies are limited. As a temporary workaround, restrict access to Copilot Studio based on the principle of least privilege. Implement strict input validation and output encoding on all user-supplied data within Copilot Studio flows. Consider using a Web Application Firewall (WAF) to filter out potentially malicious requests. Monitor Copilot Studio logs for suspicious activity, such as unusual script execution or unexpected redirects. Once Microsoft releases a patched version, prioritize upgrading to that version to fully remediate the vulnerability. After upgrade, confirm by reviewing Copilot Studio logs for any errors or unexpected behavior.