Auth bypass in Openzfs
CVE-2026-79619
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.
Vulnerability class: Broken Access Control
Affected products
Weakness classification (CWE)
References
- security@ubuntu.com (patch)
- security@ubuntu.com (vendor-advisory)
- security@ubuntu.com (product)
- security@ubuntu.com (product)
- security@ubuntu.com (product)