On Darwin, user's trust preferences for root certificates were not honored. If the user had a root certificate loaded in their Keychain that was explicitly not trusted, a Go program would still verify a connection using that root certificate.

The net/http package's Request.ParseMultipartForm method starts writing to temporary files once the request body size surpasses the given "maxMemory" limit. It was possible for an attacker to generate a multipart request crafted such that the server ran out of file descriptors.

A bug in the standard library ScalarMult implementation of curve P-256 for amd64 architectures in Go before 1.7.6 and 1.8.x before 1.8.2 causes incorrect results to be generated for specific input points. An adaptive attack can be mounted to progressively extract the scalar input to ScalarMult by submitting crafted points and observing failures to the derive correct output. This leads to a full key recovery attack against static ECDH, as used in popular JWT libraries.