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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-79619
StatePUBLISHED
Assignercanonical
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-26 13:19:24 UTC
Updated2026-08-26 16:16:43 UTC
DescriptionOn 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.

Risk And Classification

Primary CVSS: v4.0 7.3 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-863 | CWE-863 CWE-863 Incorrect Authorization

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.3HIGHCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS7.3HIGHCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA OpenZFS OpenZFS affected 2.2.11 semver Linux
CNA OpenZFS OpenZFS affected 2.3.0 2.3.9 semver Linux
CNA OpenZFS OpenZFS affected 2.4.0 2.4.4 semver Linux

References

ReferenceSourceLinkTags
github.com/openzfs/zfs/releases/tag/zfs-2.3.9 [email protected] github.com
github.com/advisories/GHSA-mhf5-q8gw-qg9v [email protected] github.com
github.com/openzfs/zfs/releases/tag/zfs-2.4.4 [email protected] github.com
github.com/openzfs/zfs/releases/tag/zfs-2.2.11 [email protected] github.com
github.com/openzfs/zfs/pull/18959 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Erica Windisch (en)

CNA: Rob Norris (en)

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