WordPress is affected by an unauthenticated blind SSRF in the pingback feature. Because of a TOCTOU race condition between the validation checks and the HTTP request, attackers can reach internal hosts that are explicitly forbidden.
{
"versions": [
{
"introduced": "4.2"
},
{
"last_affected": "6.1.1"
},
{
"introduced": "0"
},
{
"last_affected": "4.1-NA"
}
]
}