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.
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.