diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 1d31ce9..226f8e3 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -212,8 +212,11 @@
 static int ssl_tls13_sig_alg_is_offered( const mbedtls_ssl_context *ssl,
                                          uint16_t proposed_sig_alg )
 {
-    for( const uint16_t *sig_alg = mbedtls_ssl_conf_get_sig_algs( ssl->conf );
-         *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++ )
+    const uint16_t *sig_alg = mbedtls_ssl_get_sig_algs( ssl );
+    if( sig_alg == NULL )
+        return( 0 );
+
+    for( ; *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++ )
     {
         if( *sig_alg == proposed_sig_alg )
             return( 1 );