The Int.Exp Montgomery code in the math/big library in Go 1.5.x before 1.5.3 mishandles carry propagation and produces incorrect output, which makes it easier for attackers to obtain private RSA keys via unspecified vectors.
crpyto/tls in Go 1.1 before 1.3.2, when SessionTicketsDisabled is enabled, allows man-in-the-middle attackers to spoof clients via unspecified vectors.