Race condition in the NPObjWrapper_NewResolve function in modules/plugin/base/src/nsJSNPRuntime.cpp in xul.dll in Mozilla Firefox 3 before 3.0.11 might allow remote attackers to execute arbitrary code via a page transition during Java applet loading, related to a use-after-free vulnerability for memory associated with a destroyed Java object.
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg00657.html
https://www.redhat.com/archives/fedora-package-announce/2009-June/msg00574.html
https://rhn.redhat.com/errata/RHSA-2009-1095.html
https://bugzilla.redhat.com/show_bug.cgi?id=503579
http://www.mozilla.org/security/announce/2009/mfsa2009-28.html