---
title: "CVE-2026-99079: Linux kernel - Use After Free"
description: "Linux kernel contains a use-after-free vulnerability in net/mlx5e caused by stale XSK buffer release on refill retry in legacy cyclic RQ, letting attackers cause double publication of UMEM frames, exploit requires AF_XDP socket RX ring to be full."
url: https://panop.io/threat-heartbeat/CVE-2026-99079/
---

# CVE-2026-99079 Linux kernel - Use After Free

Linux kernel contains a use-after-free vulnerability in net/mlx5e caused by stale XSK buffer release on refill retry in legacy cyclic RQ, letting attackers cause double publication of UMEM frames, exploit requires AF\_XDP socket RX ring to be full.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.21% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-99079)

## Details

Type

Use After Free

Impact

Data Tampering

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

23 October 2026

Updated

25 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for net/mlx5e stale XSK buffer release.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-99079](https://nvd.nist.gov/vuln/detail/CVE-2026-99079)
- [https://git.kernel.org/stable/c/32bbb870078d467479965c21bbc4960c57eea208](https://git.kernel.org/stable/c/32bbb870078d467479965c21bbc4960c57eea208)
- [https://git.kernel.org/stable/c/34d1db2b18e1c1d189e34dd51923e031815f88e3](https://git.kernel.org/stable/c/34d1db2b18e1c1d189e34dd51923e031815f88e3)
- [https://git.kernel.org/stable/c/639522e5056cade578a324acfa993ec6c9f7f5dc](https://git.kernel.org/stable/c/639522e5056cade578a324acfa993ec6c9f7f5dc)
- [https://git.kernel.org/stable/c/655f47477054d19de3b138840be229a1a4490d0c](https://git.kernel.org/stable/c/655f47477054d19de3b138840be229a1a4490d0c)
- [https://git.kernel.org/stable/c/e01620844c5c88b6fcf819d171df8e3976a0e76f](https://git.kernel.org/stable/c/e01620844c5c88b6fcf819d171df8e3976a0e76f)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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