diff --git a/core/rtw_ap.c b/core/rtw_ap.c
index 6d41be8..374082a 100644
--- a/core/rtw_ap.c
+++ b/core/rtw_ap.c
@@ -1931,8 +1931,7 @@ int rtw_check_beacon_data(_adapter *padapter, u8 *pbuf,  int len)
 	if (!MLME_IS_AP(padapter) && !MLME_IS_MESH(padapter))
 		return _FAIL;
 
-
-	if (len > MAX_IE_SZ)
+	if (len < 0 || len > MAX_IE_SZ)
 		return _FAIL;
 
 	pbss_network->IELength = len;