access parameter manipulation detected in IM 140

A friend of mine said he found the following Cross-Script vulnerability in IM 140
STYLE_URL=<script>var%20beta_on_test_variable=61549993%3Balert(beta_test_variable)%3B</script>
Any idea what this could do and how to fix it?
STYLE_URL=<script>var%20beta_on_test_variable=61549993%3Balert(beta_test_variable)%3B</script>
Any idea what this could do and how to fix it?