diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 6e304e840d..5849799f05 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -1757,13 +1757,12 @@ int socket_address_parse_vsock(SocketAddress *ret_address, const char *s) {
 int vsock_get_local_cid(unsigned *ret) {
         _cleanup_close_ int vsock_fd = -EBADF;
 
-        assert(ret);
-
         vsock_fd = open("/dev/vsock", O_RDONLY|O_CLOEXEC);
         if (vsock_fd < 0)
                 return log_debug_errno(errno, "Failed to open /dev/vsock: %m");
 
-        if (ioctl(vsock_fd, IOCTL_VM_SOCKETS_GET_LOCAL_CID, ret) < 0)
+        unsigned tmp;
+        if (ioctl(vsock_fd, IOCTL_VM_SOCKETS_GET_LOCAL_CID, ret ?: &tmp) < 0)
                 return log_debug_errno(errno, "Failed to query local AF_VSOCK CID: %m");
 
         return 0;