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.