Do a search on Flash, especially on security sites (Internet
Storm Center, National Vulnerability Database from Dept. of
Homeland Security, etc.). Set your time frame to span a few years.
You'll find numerous problems cropping up several times a year. If
problems came up only once every few years we wouldn't be concerned
but sadly this isn't the case.
Yet another Flash security hole posted on Adobe just
yesterday:
Release date: October 7, 2008
Vulnerability identifier: APSA08-08
Platform: All Platforms
Affected Software: Adobe Flash Player 9.0.124.0 and earlier
Summary
Adobe is aware of recently published reports of a
‘Clickjacking’ issue in multiple web browsers that
could allow an attacker to lure a web browser user into unknowingly
clicking on a link or dialog. It has been determined that this
potential "Clickjacking" issue affects Adobe Flash Player. Adobe is
working to address this issue in an upcoming update to Flash
Player.
Severity Rating
Adobe categorizes this as a critical issue.
http://www.adobe.com/support/security/advisories/apsa08-08.html