A stored cross-site scripting (XSS) vulnerability exists in various firmware versions of the legacy IBM System x IMM (IMM v1) embedded Baseboard Management Controller (BMC). This vulnerability could allow an unauthenticated user to cause JavaScript code to be stored in the IMM log which may then be executed in the user's web browser when IMM log records containing the JavaScript code are viewed. The JavaScript code is not executed on IMM itself. The later IMM2 (IMM v2) is not affected.