Well, it is an issue if you can use it to break out of containers that use --no-pivot-root (you can). fd-related escapes are possible for pivot_root(2) but are

Well, it is an issue if you can use it to break out of containers that use --no-pivot-root (you can). fd-related escapes are possible for pivot_root(2) but are usually not as trivial as the one for chroot(2). Also there are other attacks against chroot(2) which don't make use of fd-related escapes (nd->root protections in pathname lookup are very minimal and there are lots of ways to trick them).