diff -Naur strongswan-5.6.2-orig/src/libcharon/plugins/stroke/stroke_socket.c strongswan-5.6.2/src/libcharon/plugins/stroke/stroke_socket.c
--- strongswan-5.6.2-orig/src/libcharon/plugins/stroke/stroke_socket.c	2017-11-09 10:57:30.000000000 -0500
+++ strongswan-5.6.2/src/libcharon/plugins/stroke/stroke_socket.c	2018-05-24 00:00:32.382953618 -0400
@@ -628,6 +628,11 @@
 		return FALSE;
 	}
 
+	if (len < offsetof(stroke_msg_t, buffer))
+	{
+		DBG1(DBG_CFG, "invalid stroke message length %d", len);
+		return FALSE;
+	}
 	/* read message (we need an additional byte to terminate the buffer) */
 	msg = malloc(len + 1);
 	msg->length = len;