This indicates an attack attempt against a Cross Site Scripting vulnerability in IBM Rational Clearcase.
The vulnerability is caused by an error when the vulnerable software handles a malicious request. It allows a remote attacker to execute arbitrary an script via sending a crafted web request.
ClearCase RWP server in IBM Rational ClearCase 7.0.0 before 22.214.171.124, and 126.96.36.199-RATL-RCC-IFIX02 and possibly other 7.0.1 versions before 188.8.131.52
Upgrade to the latest version.