OpenZFS through 2.1.13 and 2.2.x through 2.2.1, in certain scenarios involving applications that try to rely on efficient copying of file data, can replace file contents with zero-valued bytes and thus potentially disable security mechanisms. NOTE: this issue is not always security related, but can be security related in realistic situations. A possible example is cp, from a recent GNU Core Utilities (coreutils) version, when attempting to preserve a rule set for denying unauthorized access. (One might use cp when configuring access control, such as with the /etc/hosts.deny file specified in the IBM Support reference.) NOTE: this issue occurs less often in version 2.2.1, and in versions before 2.1.4, because of the default configuration in those versions.
https://www.theregister.com/2023/12/04/two_new_versions_of_openzfs/
https://news.ycombinator.com/item?id=38770168
https://news.ycombinator.com/item?id=38405731
https://lists.debian.org/debian-lts-announce/2024/03/msg00019.html
https://github.com/openzfs/zfs/releases/tag/zfs-2.2.2
https://github.com/openzfs/zfs/releases/tag/zfs-2.1.14
https://github.com/openzfs/zfs/pull/15571
https://github.com/openzfs/zfs/issues/15526