CVE-2026-79619

OpenZFS: user-namespace capability check allows unprivileged local authorization bypass

Published Aug 26, 2026 CVSS 4.0 · 7.3 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8705-1 OpenZFS vulnerability
Ubuntu USN Ubuntu USN USN-8705-2 OpenZFS vulnerability
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Openzfs
Openzfs openzfs
Vendors & Products Openzfs
Openzfs openzfs
Type Values Removed Values Added
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.
Title OpenZFS: user-namespace capability check allows unprivileged local authorization bypass
Weaknesses CWE-863
References
Metrics cvssV4_0

{'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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
canonical
Published
Updated
Aug 27, 2026, 5:32 PM
Reserved
Aug 25, 2026, 8:10 AM
Status
Awaiting Analysis
Published
Aug 26, 2026, 1:19 PM
Modified
Aug 28, 2026, 3:24 PM