One would assume that prominent security sites would protect against cross-site scripting. But you know what they say about assuming anything...

Thirty XSS vulnerabilities spotted on McAfee, Symantec and VeriSign sites - Computerworld

The report, from security watchdog site XSSed, verified 30 cross-site scripting (XSS) vulnerabilities across the sites of McAfee, Symantec and VeriSign. The flaws could be used to launch scams or implant malicious code on the systems of visiting users, according to XSSed.