On Linux, several OpenZFS ioctl authorization checks accept a capability held only within a user-created, unprivileged namespace as equivalent to real host privilege, allowing an unprivileged local user to perform operations that should require root. Affected operations include pool-administrative operations (eg create, import, destroy), pool event log access (zpool events) and fault injection (zinject). Exploiting the problem requires only that the local user is permitted to open /dev/zfs (governed by local device permissions) and that the kernel permits unprivileged user namespace creation. No prior access to the target pool or its underlying devices is needed.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade zfs-linux | Aug 27, 2026 | Aug 27, 2026 |
| Ubuntu | — | Upgrade zfs-dkmsUpgrade zfs-dkms (Ubuntu Pro)Upgrade zfsutils-linux (Ubuntu Pro)Upgrade libzfs4linuxUpgrade libzfs2linux (Ubuntu Pro)Upgrade libzfs7linuxUpgrade libuutil1linux (Ubuntu Pro)Upgrade zfsutils-linux | Aug 31, 2026 | Aug 27, 2026 |
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