TI-2026-55131 Aliases CVE-2026-79619 GHSA-5v2p-vxxv-r62r

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

LOW 33CWE-863Published 2026-08-26 · Updated 2026-08-27

Key facts

Attack vector: Local
Privileges required: Low
User interaction: None
Attack complexity: Low
Attack requirements: Present
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00198 9th percentileScored 2026-11-07

Fix Fixed OpenZFS (OpenZFS): 2.2.11, 2.3.9, 2.4.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
OpenZFS	OpenZFS	0.7.0 to before 2.2.11; 2.3.0 to before 2.3.9; 2.4.0 to before 2.4.4	2.2.11, 2.3.9, 2.4.4	Patch available	CNA

OpenZFS VendorOpenZFS Affected 0.7.0 to before 2.2.11; 2.3.0 to before 2.3.9; 2.4.0 to before 2.4.4 Fixed in 2.2.11, 2.3.9, 2.4.4 Patch available CNA

Remediation

Fix · CNA OpenZFS (OpenZFS) Fixed in 2.2.11, 2.3.9, 2.4.4

Timeline

2026-10-02 Threatist record created from CVE-2026-79619
2026-10-03 Alias added: GHSA-5v2p-vxxv-r62r

References

Patch 1

https://github.com/openzfs/zfs/pull/18959

Advisory 1

https://github.com/advisories/GHSA-mhf5-q8gw-qg9v

Other 4

TI-2023-26934 OpenZFS through 2.1.13 and 2.2.x through 2.2.1, in certain scenarios involving… CVSS 3.1HIGH 7.5
TI-2013-06216 An issue was discovered in OpenZFS through 2.0.3. CVSS 3.1HIGH 7.5
TI-2020-15174 OpenZFS before 2.0.0-rc1, when used on FreeBSD, allows execute permissions for all directories. CVSS 3.1HIGH 7.8
TI-2020-15175 OpenZFS before 2.0.0-rc1, when used on FreeBSD, misinterprets group permissions as user… CVSS 3.1HIGH 7.8

Sources

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