Attack Chain

1. Attacker gains access to a RabbitMQ account with privileges to create or modify vhosts.
2. Attacker crafts a malicious vhost name containing JavaScript code, such as <script>alert("XSS");</script>.
3. Attacker creates or modifies an existing vhost with the crafted, malicious name through the RabbitMQ management UI or API.
4. A user, typically an administrator, logs into the RabbitMQ management UI.
5. The management UI displays the list of vhosts, including the attacker’s maliciously named vhost.
6. The unsanitized vhost name is rendered in the user’s browser, executing the embedded JavaScript code.
7. The injected script executes in the context of the user’s browser session, potentially stealing cookies or performing other actions on behalf of the user.
8. Attacker uses stolen session cookies to impersonate the administrator or other privileged user.

Impact

Successful exploitation of CVE-2026-44839 allows an attacker to execute arbitrary JavaScript code within the RabbitMQ management UI in the context of a user’s browser. This can lead to account compromise through session hijacking, potentially granting the attacker full administrative control over the RabbitMQ server. The impact ranges from data exfiltration to denial of service, depending on the privileges of the compromised account and the attacker’s objectives. The number of affected users depends on the RabbitMQ deployment size.

Recommendation

• Upgrade RabbitMQ to a patched version that includes proper sanitization of vhost names to prevent XSS attacks (refer to vendor advisory).
• Implement input validation and output encoding on the RabbitMQ management UI to sanitize vhost names (and other user-controlled inputs).
• Deploy the Sigma rule “Detect Suspicious RabbitMQ vhost Creation with Script Tags” to identify attempts to inject malicious code via vhost names.
• Regularly review and audit RabbitMQ user privileges to minimize the impact of potential account compromise.