diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
index c509ebf42..cf8c93d51 100644
--- a/src/ap/hostapd.c
+++ b/src/ap/hostapd.c
@@ -1385,7 +1385,7 @@ static void fst_hostapd_get_channel_info_cb(void *ctx,
 }
 
 
-static void fst_hostapd_set_ies_cb(void *ctx, struct wpabuf *fst_ies)
+static void fst_hostapd_set_ies_cb(void *ctx, const struct wpabuf *fst_ies)
 {
 	struct hostapd_data *hapd = ctx;
 
diff --git a/src/ap/hostapd.h b/src/ap/hostapd.h
index 5c94bc1bd..89a1e8b5d 100644
--- a/src/ap/hostapd.h
+++ b/src/ap/hostapd.h
@@ -312,7 +312,7 @@ struct hostapd_iface {
 	unsigned int cac_started:1;
 #ifdef CONFIG_FST
 	struct fst_iface *fst;
-	struct wpabuf *fst_ies;
+	const struct wpabuf *fst_ies;
 #endif /* CONFIG_FST */
 
 	/*
diff --git a/src/fst/fst.h b/src/fst/fst.h
index bfeba6367..0c0e435b9 100644
--- a/src/fst/fst.h
+++ b/src/fst/fst.h
@@ -70,9 +70,9 @@ struct fst_wpa_obj {
 	/**
 	 * set_ies - Set interface's MB IE
 	 * @ctx: User context %ctx
-	 * @fst_ies: MB IE buffer
+	 * @fst_ies: MB IE buffer (owned by FST module)
 	 */
-	void (*set_ies)(void *ctx, struct wpabuf *fst_ies);
+	void (*set_ies)(void *ctx, const struct wpabuf *fst_ies);
 
 	/**
 	 * send_action - Send FST Action frame via the interface
diff --git a/src/fst/fst_iface.h b/src/fst/fst_iface.h
index 26cb38ddd..4670d894f 100644
--- a/src/fst/fst_iface.h
+++ b/src/fst/fst_iface.h
@@ -85,7 +85,7 @@ static inline int fst_iface_get_hw_modes(struct fst_iface *i,
 }
 
 static inline void fst_iface_set_ies(struct fst_iface *i,
-				     struct wpabuf *fst_ies)
+				     const struct wpabuf *fst_ies)
 {
 	i->iface_obj.set_ies(i->iface_obj.ctx, fst_ies);
 }
diff --git a/wpa_supplicant/wpa_supplicant.c b/wpa_supplicant/wpa_supplicant.c
index e1865d5f7..277265e8f 100644
--- a/wpa_supplicant/wpa_supplicant.c
+++ b/wpa_supplicant/wpa_supplicant.c
@@ -3751,7 +3751,7 @@ static int wpas_fst_get_hw_modes(void *ctx, struct hostapd_hw_modes **modes)
 }
 
 
-static void wpas_fst_set_ies_cb(void *ctx, struct wpabuf *fst_ies)
+static void wpas_fst_set_ies_cb(void *ctx, const struct wpabuf *fst_ies)
 {
 	struct wpa_supplicant *wpa_s = ctx;
 
diff --git a/wpa_supplicant/wpa_supplicant_i.h b/wpa_supplicant/wpa_supplicant_i.h
index a4e99ede9..7154bb04e 100644
--- a/wpa_supplicant/wpa_supplicant_i.h
+++ b/wpa_supplicant/wpa_supplicant_i.h
@@ -980,7 +980,7 @@ struct wpa_supplicant {
 
 #ifdef CONFIG_FST
 	struct fst_iface *fst;
-	struct wpabuf *fst_ies;
+	const struct wpabuf *fst_ies;
 	struct wpabuf *received_mb_ies;
 #endif /* CONFIG_FST */
 };