In Go before 1.15.13 and 1.16.x before 1.16.5, some configurations of ReverseProxy (from net/http/httputil) result in a situation where an attacker is able to drop arbitrary headers.
{
"versions": [
{
"introduced": "0"
},
{
"fixed": "1.15.13"
},
{
"introduced": "1.16.0"
},
{
"fixed": "1.16.5"
}
]
}