Incorrect authorization in zfs - CVE-2026-79619
Published: September 1, 2026
Vulnerability identifier: #VU146542
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-79619
CWE-ID: CWE-863
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to bypass authorization checks and perform administrative OpenZFS operations.
The vulnerability exists due to incorrect authorization in several OpenZFS ioctl authorization checks when evaluating CAP_SYS_ADMIN within a user-created namespace. A local user can create an unprivileged user namespace and invoke affected ioctls to bypass authorization checks and perform administrative OpenZFS operations.
Exploitation requires that the user can open /dev/zfs and that the kernel permits unprivileged user namespace creation. No prior access to the target pool or its underlying devices is required.
Affected software
zfs
Ubuntu
zfs-linux (Ubuntu package)
Ubuntu
zfs-linux (Ubuntu package)
How to mitigate CVE-2026-79619
Install security update from vendor's website.
zfs - addressed in versions 2.2.11, 2.3.9, 2.4.4
zfs-linux (Ubuntu package) - addressed in versions 0.7.5-1ubuntu16.12+esm1, 0.8.3-1ubuntu12.18+esm1, 2.1.5-1ubuntu6~22.04.7, 2.2.2-0ubuntu9.5, 2.4.1-1ubuntu5.1
zfs-linux (Ubuntu package) - addressed in versions 0.7.5-1ubuntu16.12+esm1, 0.8.3-1ubuntu12.18+esm1, 2.1.5-1ubuntu6~22.04.7, 2.2.2-0ubuntu9.5, 2.4.1-1ubuntu5.1