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.
Exploitability
AV:NAC:HPR:NUI:NScope
S:UImpact
C:HI:NA:N5.9/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N