Mozilla Firefox 68 : A vulnerability exists where it possible to force Network Security Services (NSS) to sign <code>CertificateVerify</code> with PKCS#1 v1.5 signatures when those are the only ones advertised by server in <code>CertificateRequest</code> in TLS 1.3. PKCS#1 v1.5 signatures should not be used for TLS 1.3 messages.