diff --git a/ChangeLog b/ChangeLog
index 017d6a279..8ef395107 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,8 @@ Bugfix
    * Fix issue in Makefile that prevented building using armar. #386
    * Fix bug in mbedtls_x509_crt_parse that caused trailing extra data in the
      buffer after DER certificates to be included in the raw representation.
+   * Fix issue that caused a crash if invalid curves were passed to
+     mbedtls_ssl_conf_curves. #373
 
 Changes
    * On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5,
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 09fc3377c..1d8b33fa3 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -269,6 +269,12 @@ static void ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
     for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
     {
 #endif
+        if( info == NULL )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid curve in ssl configuration" ) );
+            return;
+        }
+
         elliptic_curve_len += 2;
     }
 
@@ -288,7 +294,6 @@ static void ssl_write_supported_elliptic_curves_ext( mbedtls_ssl_context *ssl,
     for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
     {
 #endif
-
         elliptic_curve_list[elliptic_curve_len++] = info->tls_id >> 8;
         elliptic_curve_list[elliptic_curve_len++] = info->tls_id & 0xFF;
     }