Executive brief
RabbitMQ is a messaging and streaming broker. From 4.2.0 until 4.2.8 and 4.3.2, set_token_auth/2 inserted a bearer token from the Authorization header or access_token cookie into OAuth bootstrap JavaScript without escaping, allowing attacker-controlled token content to execute JavaScript in the management UI origin. The endpoint is exposed before authentication only when management.oauth_enabled is true, and exploitation through the cookie path additionally requires the attacker to plant an access_token cookie on the management host. This issue is fixed in versions 4.2.8 and 4.3.2.