diff --git a/src/chain.c b/src/chain.c
index e25eb0f5934b..e98af1360912 100644
--- a/src/chain.c
+++ b/src/chain.c
@@ -371,6 +371,7 @@ const void *nftnl_chain_get_data(const struct nftnl_chain *c, uint16_t attr,
 		*data_len = strlen(c->dev) + 1;
 		return c->dev;
 	case NFTNL_CHAIN_DEVICES:
+		*data_len = 0;
 		return &c->dev_array[0];
 	}
 	return NULL;
diff --git a/src/flowtable.c b/src/flowtable.c
index 6e18dde8242e..18a3c98ea62d 100644
--- a/src/flowtable.c
+++ b/src/flowtable.c
@@ -237,6 +237,7 @@ const void *nftnl_flowtable_get_data(const struct nftnl_flowtable *c,
 		*data_len = sizeof(int32_t);
 		return &c->family;
 	case NFTNL_FLOWTABLE_DEVICES:
+		*data_len = 0;
 		return &c->dev_array[0];
 	case NFTNL_FLOWTABLE_SIZE:
 		*data_len = sizeof(int32_t);