Index: uspace/lib/ieee80211/src/ieee80211.c
===================================================================
--- uspace/lib/ieee80211/src/ieee80211.c	(revision 5f97ef445e6e5648a8b8c902eb0f655d579336b4)
+++ uspace/lib/ieee80211/src/ieee80211.c	(revision e71c023c4a684de0901f85c39d31d40c8f200ba7)
@@ -571,8 +571,10 @@
 	/* Init crypto data. */
 	bool add_mic = false;
+	const size_t max_head_space = max(IEEE80211_TKIP_HEADER_LENGTH,
+	    IEEE80211_CCMP_HEADER_LENGTH);
 	size_t head_space = 0, mic_space = 0;
 	uint16_t crypto = 0;
-	uint8_t head_data[head_space];
-	memset(head_data, 0, head_space);
+	uint8_t head_data[max_head_space];
+	memset(head_data, 0, max_head_space);
 
 	// TODO: Distinguish used key (pair/group) by dest address ?