diff --git a/src/libcharon/sa/ike_sa.c b/src/libcharon/sa/ike_sa.c
index 7b38e0268..3ef9801e0 100644
--- a/src/libcharon/sa/ike_sa.c
+++ b/src/libcharon/sa/ike_sa.c
@@ -2150,8 +2150,11 @@ METHOD(ike_sa_t, destroy, void,
 	/* remove attributes first, as we pass the IKE_SA to the handler */
 	while (array_remove(this->attributes, ARRAY_TAIL, &entry))
 	{
-		hydra->attributes->release(hydra->attributes, entry.handler,
-								   this->other_id, entry.type, entry.data);
+		if (entry.handler)
+		{
+			hydra->attributes->release(hydra->attributes, entry.handler,
+									   this->other_id, entry.type, entry.data);
+		}
 		free(entry.data.ptr);
 	}
 	/* uninstall CHILD_SAs before virtual IPs, otherwise we might kill
diff --git a/src/libcharon/sa/ike_sa.h b/src/libcharon/sa/ike_sa.h
index d162539db..5dc7326a4 100644
--- a/src/libcharon/sa/ike_sa.h
+++ b/src/libcharon/sa/ike_sa.h
@@ -978,6 +978,9 @@ struct ike_sa_t {
 	 * registered at the IKE_SA. Attributes are inherit()ed and get released
 	 * when the IKE_SA is closed.
 	 *
+	 * Unhandled attributes are passed as well, but with a NULL handler. They
+	 * do not get released.
+	 *
 	 * @param handler		handler installed the attribute, use for release()
 	 * @param type			configuration attribute type
 	 * @param data			associated attribute data
diff --git a/src/libcharon/sa/ikev1/tasks/mode_config.c b/src/libcharon/sa/ikev1/tasks/mode_config.c
index 55fb390ce..d678f1942 100644
--- a/src/libcharon/sa/ikev1/tasks/mode_config.c
+++ b/src/libcharon/sa/ikev1/tasks/mode_config.c
@@ -139,11 +139,8 @@ static void handle_attribute(private_mode_config_t *this,
 	handler = hydra->attributes->handle(hydra->attributes,
 							this->ike_sa->get_other_id(this->ike_sa), handler,
 							ca->get_type(ca), ca->get_chunk(ca));
-	if (handler)
-	{
-		this->ike_sa->add_configuration_attribute(this->ike_sa,
-				handler, ca->get_type(ca), ca->get_chunk(ca));
-	}
+	this->ike_sa->add_configuration_attribute(this->ike_sa,
+							handler, ca->get_type(ca), ca->get_chunk(ca));
 }
 
 /**
diff --git a/src/libcharon/sa/ikev2/tasks/ike_config.c b/src/libcharon/sa/ikev2/tasks/ike_config.c
index 1a4c21b54..89b15ea5f 100644
--- a/src/libcharon/sa/ikev2/tasks/ike_config.c
+++ b/src/libcharon/sa/ikev2/tasks/ike_config.c
@@ -130,11 +130,8 @@ static void handle_attribute(private_ike_config_t *this,
 	handler = hydra->attributes->handle(hydra->attributes,
 							this->ike_sa->get_other_id(this->ike_sa), handler,
 							ca->get_type(ca), ca->get_chunk(ca));
-	if (handler)
-	{
-		this->ike_sa->add_configuration_attribute(this->ike_sa,
-				handler, ca->get_type(ca), ca->get_chunk(ca));
-	}
+	this->ike_sa->add_configuration_attribute(this->ike_sa,
+							handler, ca->get_type(ca), ca->get_chunk(ca));
 }
 
 /**