Google V8 as used in Google Chrome before 38.0.2125.101 does not properly track JavaScript heap-memory allocations as allocations of uninitialized memory and does not properly concatenate arrays of double-precision floating-point numbers which allows remote attackers to obtain sensitive information via crafted JavaScript code related to the PagedSpace::AllocateRaw and NewSpace::AllocateRaw functions in heap/spaces-inl.h the LargeObjectSpace::AllocateRaw function in heap/spaces.cc and the Runtime_ArrayConcat function in runtime.cc.