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.
https://seclists.org/fulldisclosure/2026/Aug/40
https://github.com/openzfs/zfs/releases/tag/zfs-2.4.4
https://github.com/openzfs/zfs/releases/tag/zfs-2.3.9
https://github.com/openzfs/zfs/releases/tag/zfs-2.2.11
Published: 2026-08-26
Updated: 2026-08-27
Base Score: 7.2
Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C
Severity: High
Base Score: 7.8
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High
Base Score: 7.3
Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00138