NSSecureTextField in AppKit in Apple Mac OS X 10.4.6 does not re-enable secure event input under certain circumstances, which could allow other applications in the window session to monitor input characters and keyboard events.
https://exchange.xforce.ibmcloud.com/vulnerabilities/26404
http://www.vupen.com/english/advisories/2006/1779
http://www.us-cert.gov/cas/techalerts/TA06-132A.html
http://www.securityfocus.com/bid/17951
http://secunia.com/advisories/20077
http://lists.apple.com/archives/security-announce/2006/May/msg00003.html