The Utf8DecoderBase::WriteUtf16Slow function in unicode-decoder.cc in Google V8, as used in Node.js before 0.12.6, io.js before 1.8.3 and 2.x before 2.3.3, and other products, does not verify that there is memory available for a UTF-16 surrogate pair, which allows remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via a crafted byte sequence.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.