diff --git a/sys/dev/ipw/if_ipw.c b/sys/dev/ipw/if_ipw.c
index bab7a72603e4..7a52d32cd17c 100644
--- a/sys/dev/ipw/if_ipw.c
+++ b/sys/dev/ipw/if_ipw.c
@@ -1321,8 +1321,10 @@ ipw_tx_start(struct ifnet *ifp, struct mbuf *m0, struct ieee80211_node *ni)
 
 	if (wh->i_fc[1] & IEEE80211_FC1_WEP) {
 		k = ieee80211_crypto_encap(ic, ni, m0);
-		if (k == NULL)
+		if (k == NULL) {
+			m_freem(m0);
 			return ENOBUFS;
+		}
 
 		/* packet header may have moved, reset our local pointer */
 		wh = mtod(m0, struct ieee80211_frame *);
diff --git a/sys/dev/iwi/if_iwi.c b/sys/dev/iwi/if_iwi.c
index e6aa051c7c5c..35d9674e28f7 100644
--- a/sys/dev/iwi/if_iwi.c
+++ b/sys/dev/iwi/if_iwi.c
@@ -1355,8 +1355,10 @@ iwi_tx_start(struct ifnet *ifp, struct mbuf *m0, struct ieee80211_node *ni)
 	bcopy(mtod(m0, struct ieee80211_frame *), &wh, sizeof (struct ieee80211_frame));
 	if (wh.i_fc[1] & IEEE80211_FC1_WEP) {
 		k = ieee80211_crypto_encap(ic, ni, m0);
-		if (k == NULL)
+		if (k == NULL) {
+			m_freem(m0);
 			return ENOBUFS;
+		}
 	}
 
 	if (sc->sc_drvbpf != NULL) {
diff --git a/sys/dev/ral/if_ral.c b/sys/dev/ral/if_ral.c
index 9e6cf74b53ae..9877a3dceb70 100644
--- a/sys/dev/ral/if_ral.c
+++ b/sys/dev/ral/if_ral.c
@@ -1900,8 +1900,10 @@ ral_tx_data(struct ral_softc *sc, struct mbuf *m0, struct ieee80211_node *ni)
 
 	if (wh->i_fc[1] & IEEE80211_FC1_WEP) {
 		k = ieee80211_crypto_encap(ic, ni, m0);
-		if (k == NULL)
+		if (k == NULL) {
+			m_freem(m0);
 			return ENOBUFS;
+		}
 
 		/* packet header may have moved, reset our local pointer */
 		wh = mtod(m0, struct ieee80211_frame *);
diff --git a/sys/dev/usb/if_ural.c b/sys/dev/usb/if_ural.c
index 55892220eb18..758edc08cf6c 100644
--- a/sys/dev/usb/if_ural.c
+++ b/sys/dev/usb/if_ural.c
@@ -1202,8 +1202,10 @@ ural_tx_data(struct ural_softc *sc, struct mbuf *m0, struct ieee80211_node *ni)
 
 	if (wh->i_fc[1] & IEEE80211_FC1_WEP) {
 		k = ieee80211_crypto_encap(ic, ni, m0);
-		if (k == NULL)
+		if (k == NULL) {
+			m_freem(m0);
 			return ENOBUFS;
+		}
 
 		/* packet header may have moved, reset our local pointer */
 		wh = mtod(m0, struct ieee80211_frame *);