OTP is a set of Erlang libraries, which consists of the Erlang runtime system, a number of ready-to-use components mainly written in Erlang, and a set of design principles for Erlang programs. A regression was introduced into the ssl application of OTP starting at OTP-25.3.2.8, OTP-26.2, and OTP-27.0, resulting in a server or client verifying the peer when incorrect extended key usage is presented (i.e., a server will verify a client if they have server auth ext key usage and vice versa).
The product does not validate, or incorrectly validates, a certificate.