This powershell script generates a new certificate, removes the old certificate assignments from the IISExpress ssl ports and adds the newly generated one. The certificate is also copied over to the Trusted Root Certificate Authorities.

UpdateIISExpressCertificate.ps1

$cert = New-SelfSignedCertificate -DnsName "localhost", "localhost" -CertStoreLocation "cert:\LocalMachine\My" -NotAfter (Get-Date).AddYears(5)
$thumb = $cert.GetCertHashString()

For ($i=44300; $i -le 44399; $i++) {
    netsh http delete sslcert ipport=0.0.0.0:$i
}

For ($i=44300; $i -le 44399; $i++) {
    netsh http add sslcert ipport=0.0.0.0:$i certhash=$thumb appid=`{214124cd-d05b-4309-9af9-9caa44b2b74a`}
}

$StoreScope = 'LocalMachine'
$StoreName = 'root'

$Store = New-Object  -TypeName System.Security.Cryptography.X509Certificates.X509Store  -ArgumentList $StoreName, $StoreScope
$Store.Open([System.Security.Cryptography.X509Certificates.OpenFlags]::ReadWrite)
$Store.Add($cert)

$Store.Close()