CVE-2026-79619
OpenZFS: user-namespace capability check allows unprivileged local authorization bypass
- State
- Published
- Severity
- 7.3 High
- Published
- Aug 26, 2026
- Updated
- Aug 27, 2026
- Reserved
- Aug 25, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 7.3 High | 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 | canonical |
Weaknesses
- CWE-863 Incorrect Authorization
Affected Products
| Product | Versions |
|---|---|
OpenZFSOpenZFS |
|
References
- https://github.com/openzfs/zfs/pull/18959patch
- https://github.com/advisories/GHSA-mhf5-q8gw-qg9vvendor-advisory
- https://github.com/openzfs/zfs/releases/tag/zfs-2.4.4product
- https://github.com/openzfs/zfs/releases/tag/zfs-2.3.9product
- https://github.com/openzfs/zfs/releases/tag/zfs-2.2.11product
- https://seclists.org/fulldisclosure/2026/Aug/40mailing-list
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