According to Secunia, 92% of the 900,000 users who’ve recently run the company's Personal Software Inspector (PSI) utility have Flash Player 10 on their PCs, while 31% have Flash Player 9. The total exceeds 100% because some users’ve installed both. The most-current versions of Flash Player -- 9.0.159.0 and 10.0.22.87) -- are vulnerable to hackers conducting drive-by attacks hosted on malicious and legitimate-but-compromised sites. Antivirus vendors’ve reported hundreds, in some cases thousands, of sites launching drive-bys against Flash. “More than 9 out of every 10 Windows users are vulnerable to the Flash zero-day vulnerability that Adobe won't patch until Thursday.”