diff --git a/clients/tui/newt/nmt-newt-entry-numeric.c b/clients/tui/newt/nmt-newt-entry-numeric.c
index a52fe8689f..92855fcb2c 100644
--- a/clients/tui/newt/nmt-newt-entry-numeric.c
+++ b/clients/tui/newt/nmt-newt-entry-numeric.c
@@ -127,8 +127,8 @@ newt_entry_numeric_validate (NmtNewtEntry *entry,
 	if (!*text)
 		return priv->optional ? TRUE : FALSE;
 
-	val = _nm_utils_ascii_str_to_int64 (text, 10, priv->min, priv->max, 0);
-	return val != 0 || errno == 0;
+	val = _nm_utils_ascii_str_to_int64 (text, 10, priv->min, priv->max, G_MAXINT64);
+	return val != G_MAXINT64 || errno == 0;
 }
 
 static void
diff --git a/libnm-core/nm-setting-bond.c b/libnm-core/nm-setting-bond.c
index b36ed20851..51ce2debbc 100644
--- a/libnm-core/nm-setting-bond.c
+++ b/libnm-core/nm-setting-bond.c
@@ -175,19 +175,14 @@ nm_setting_bond_get_option (NMSettingBond *setting,
 static gboolean
 validate_int (const char *name, const char *value, const BondDefault *def)
 {
-	long num;
-	guint i;
+	guint64 num;
 
-	for (i = 0; i < strlen (value); i++) {
-		if (!g_ascii_isdigit (value[i]) && value[i] != '-')
-			return FALSE;
-	}
-
-	errno = 0;
-	num = strtol (value, NULL, 10);
-	if (errno)
+	if (!NM_STRCHAR_ALL (value, ch, g_ascii_isdigit (ch)))
 		return FALSE;
-	if (num < def->min || num > def->max)
+
+	num = _nm_utils_ascii_str_to_uint64 (value, 10, def->min, def->max, G_MAXUINT64);
+	if (   num == G_MAXUINT64
+	    && errno != 0)
 		return FALSE;
 
 	return TRUE;
diff --git a/src/supplicant/nm-supplicant-settings-verify.c b/src/supplicant/nm-supplicant-settings-verify.c
index 2ed918b602..f10bbb0431 100644
--- a/src/supplicant/nm-supplicant-settings-verify.c
+++ b/src/supplicant/nm-supplicant-settings-verify.c
@@ -157,23 +157,13 @@ validate_type_int (const struct Opt * opt,
                    const char * value,
                    const guint32 len)
 {
-	long int intval;
+	gint64 v;
 
 	g_return_val_if_fail (opt != NULL, FALSE);
 	g_return_val_if_fail (value != NULL, FALSE);
 
-	errno = 0;
-	intval = strtol (value, NULL, 10);
-	if (errno != 0)
-		return FALSE;
-
-	/* strtol returns a long, but we are dealing with ints */
-	if (intval > INT_MAX || intval < INT_MIN)
-		return FALSE;
-	if (intval > opt->int_high || intval < opt->int_low)
-		return FALSE;
-
-	return TRUE;
+	v = _nm_utils_ascii_str_to_int64 (value, 10, opt->int_low, opt->int_high, G_MININT64);
+	return v != G_MININT64 || errno == 0;
 }
 
 static gboolean