diff --git a/drivers/net/wireless/realtek/rtlwifi/core.c b/drivers/net/wireless/realtek/rtlwifi/core.c
index c53cbf3d52bdd960a44f7be0d49a5f067ac80560..294a6b43d1bce6490da944dad7d67a9262f2fc1d 100644
--- a/drivers/net/wireless/realtek/rtlwifi/core.c
+++ b/drivers/net/wireless/realtek/rtlwifi/core.c
@@ -453,7 +453,8 @@ static void _rtl_add_wowlan_patterns(struct ieee80211_hw *hw,
 	for (i = 0; i < wow->n_patterns; i++) {
 		memset(&rtl_pattern, 0, sizeof(struct rtl_wow_pattern));
 		memset(mask, 0, MAX_WOL_BIT_MASK_SIZE);
-		if (patterns[i].pattern_len > MAX_WOL_PATTERN_SIZE) {
+		if (patterns[i].pattern_len < 0 ||
+		    patterns[i].pattern_len > MAX_WOL_PATTERN_SIZE) {
 			RT_TRACE(rtlpriv, COMP_POWER, DBG_WARNING,
 				 "Pattern[%d] is too long\n", i);
 			continue;