static int ssl_check_clienthello_tlsext_early(SSL *s)
{
    int ret = SSL_TLSEXT_ERR_NOACK;
    int al = SSL_AD_UNRECOGNIZED_NAME;

#ifndef OPENSSL_NO_EC
    /*
     * The handling of the ECPointFormats extension is done elsewhere, namely
     * in ssl3_choose_cipher in s3_lib.c.
     */
    /*
     * The handling of the EllipticCurves extension is done elsewhere, namely
     * in ssl3_choose_cipher in s3_lib.c.
     */
#endif

    if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0)
        ret =
            s->ctx->tlsext_servername_callback(s, &al,
                                               s->ctx->tlsext_servername_arg);
    else if (s->initial_ctx != NULL
             && s->initial_ctx->tlsext_servername_callback != 0)
        ret =
            s->initial_ctx->tlsext_servername_callback(s, &al,
                                                       s->
                                                       initial_ctx->tlsext_servername_arg);

    switch (ret) {
    case SSL_TLSEXT_ERR_ALERT_FATAL:
        ssl3_send_alert(s, SSL3_AL_FATAL, al);
        return -1;

    case SSL_TLSEXT_ERR_ALERT_WARNING:
        ssl3_send_alert(s, SSL3_AL_WARNING, al);
        return 1;

    case SSL_TLSEXT_ERR_NOACK:
        s->servername_done = 0;
    default:
        return 1;
    }
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.