diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index 0fad64305..bcd6ce003 100644
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -1407,7 +1407,7 @@ static int fst_hostapd_send_action_cb(void *ctx, const u8 *da,
 }
 
 
-static struct wpabuf * fst_hostapd_get_mb_ie_cb(void *ctx, const u8 *addr)
+static const struct wpabuf * fst_hostapd_get_mb_ie_cb(void *ctx, const u8 *addr)
 {
 	struct hostapd_data *hapd = ctx;
 	struct sta_info *sta = ap_get_sta(hapd, addr);
diff --git a/src/fst/fst.h b/src/fst/fst.h
index 76c3823d1..bfeba6367 100644
--- a/src/fst/fst.h
+++ b/src/fst/fst.h
@@ -89,7 +89,7 @@ struct fst_wpa_obj {
 	 * @addr: Address of the STA
 	 * Returns: MB IE buffer, %NULL if no MB IE received from the STA
 	 */
-	struct wpabuf * (*get_mb_ie)(void *ctx, const u8 *addr);
+	const struct wpabuf * (*get_mb_ie)(void *ctx, const u8 *addr);
 
 	/**
 	 * update_mb_ie - Update last MB IE received from STA
diff --git a/src/fst/fst_ctrl_iface.c b/src/fst/fst_ctrl_iface.c
index 8fe8fb299..eefdc9632 100644
--- a/src/fst/fst_ctrl_iface.c
+++ b/src/fst/fst_ctrl_iface.c
@@ -560,7 +560,7 @@ static int get_peer_mbies(const char *params, char *buf, size_t buflen)
 	u8 peer_addr[ETH_ALEN];
 	struct fst_group *g;
 	struct fst_iface *iface = NULL;
-	struct wpabuf *mbies;
+	const struct wpabuf *mbies;
 
 	if (fst_read_next_text_param(params, ifname, sizeof(ifname), &endp) ||
 	    !*ifname)
@@ -659,7 +659,7 @@ static const char * band_freq(enum mb_band_id band)
 static int print_band(unsigned num, struct fst_iface *iface, const u8 *addr,
 		      char *buf, size_t buflen)
 {
-	struct wpabuf *wpabuf;
+	const struct wpabuf *wpabuf;
 	enum hostapd_hw_mode hw_mode;
 	u8 channel;
 	int ret = 0;
diff --git a/src/fst/fst_group.c b/src/fst/fst_group.c
index 9718e4e88..f6c7be943 100644
--- a/src/fst/fst_group.c
+++ b/src/fst/fst_group.c
@@ -314,21 +314,22 @@ fst_group_does_iface_appear_in_other_mbies(struct fst_group *g,
 
 	addr = fst_iface_get_peer_first(other, &ctx, TRUE);
 	for (; addr; addr = fst_iface_get_peer_next(other, &ctx, TRUE)) {
-		struct wpabuf *mbies = fst_iface_get_peer_mb_ie(other, addr);
+		const struct wpabuf *mbies;
+		u8 other_iface_peer_addr[ETH_ALEN];
+		struct fst_iface *other_new_iface;
 
-		if (mbies) {
-			u8 other_iface_peer_addr[ETH_ALEN];
-			struct fst_iface *other_new_iface =
-				fst_group_get_new_iface_by_mbie_and_band_id(
-					g,
-					wpabuf_head(mbies), wpabuf_len(mbies),
-					iface_band_id, other_iface_peer_addr);
-			if (other_new_iface == iface &&
-			    os_memcmp(iface_addr, other_iface_peer_addr,
-				      ETH_ALEN)) {
-				os_memcpy(peer_addr, addr, ETH_ALEN);
-				return TRUE;
-			}
+		mbies = fst_iface_get_peer_mb_ie(other, addr);
+		if (!mbies)
+			continue;
+
+		other_new_iface = fst_group_get_new_iface_by_mbie_and_band_id(
+			g, wpabuf_head(mbies), wpabuf_len(mbies),
+			iface_band_id, other_iface_peer_addr);
+		if (other_new_iface == iface &&
+		    os_memcmp(iface_addr, other_iface_peer_addr,
+			      ETH_ALEN) != 0) {
+			os_memcpy(peer_addr, addr, ETH_ALEN);
+			return TRUE;
 		}
 	}
 
diff --git a/src/fst/fst_iface.h b/src/fst/fst_iface.h
index 4ccea8eed..26cb38ddd 100644
--- a/src/fst/fst_iface.h
+++ b/src/fst/fst_iface.h
@@ -96,8 +96,8 @@ static inline int fst_iface_send_action(struct fst_iface *i,
 	return i->iface_obj.send_action(i->iface_obj.ctx, addr, data);
 }
 
-static inline struct wpabuf * fst_iface_get_peer_mb_ie(struct fst_iface *i,
-						       const u8 *addr)
+static inline const struct wpabuf *
+fst_iface_get_peer_mb_ie(struct fst_iface *i, const u8 *addr)
 {
 	return i->iface_obj.get_mb_ie(i->iface_obj.ctx, addr);
 }
diff --git a/src/fst/fst_session.c b/src/fst/fst_session.c
index b2f77203a..6ce5e544f 100644
--- a/src/fst/fst_session.c
+++ b/src/fst/fst_session.c
@@ -363,7 +363,7 @@ static void fst_session_handle_setup_request(struct fst_iface *iface,
 	struct fst_iface *new_iface = NULL;
 	struct fst_group *g;
 	u8 new_iface_peer_addr[ETH_ALEN];
-	struct wpabuf *peer_mbies;
+	const struct wpabuf *peer_mbies;
 	size_t plen;
 
 	if (frame_len < IEEE80211_HDRLEN + 1 + sizeof(*req))  {
diff --git a/wpa_supplicant/wpa_supplicant.c b/wpa_supplicant/wpa_supplicant.c
index 210e33aee..24c3e5a2e 100644
--- a/wpa_supplicant/wpa_supplicant.c
+++ b/wpa_supplicant/wpa_supplicant.c
@@ -3772,7 +3772,7 @@ static int wpas_fst_send_action_cb(void *ctx, const u8 *da, struct wpabuf *data)
 }
 
 
-static struct wpabuf * wpas_fst_get_mb_ie_cb(void *ctx, const u8 *addr)
+static const struct wpabuf * wpas_fst_get_mb_ie_cb(void *ctx, const u8 *addr)
 {
 	struct wpa_supplicant *wpa_s = ctx;