This indicates an attack attempt to exploit a Cross-Site Scripting vulnerability in Cacti, which was discovered by Fortinet's FortiGuard Labs.
The vulnerability exists due to insufficiently sanitizing user-supplied data in HTTP request sent to graphs.php so that remote attackers can exploit it to launch XSS attack.
Cacti Version 0.8.8c
System Compromise: Remote attackers can execute arbitrary script code within the context of the target user's browser.
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