CVE-2026-43092: xsk: validate MTU against usable frame size on bind

Q: Who is exposed to this issue?

Systems using AF_XDP zero-copy pools are exposed when the device MTU exceeds the usable UMEM frame space after headroom and tailroom are deducted. Exposure can also depend on whether the hardware's supported receive-buffer chain length can accommodate the configured MTU.

Q: What access does an attacker need?

The CVSS vector indicates local access and low privileges are required, with no user interaction. Exploitation involves binding an AF_XDP zero-copy pool using a frame-size configuration that cannot support the device MTU.

Q: What is the impact?

The reported impact is availability only. The issue can lead to a high availability impact, while no confidentiality or integrity impact is indicated.

Q: What should be done if affected?

Apply the available patch. Until patched, avoid binding AF_XDP zero-copy pools whose usable UMEM frame size, after headroom and tailroom, is smaller than the configured device MTU, and ensure the hardware's supported XSK receive-buffer chaining can satisfy that MTU.

Published May 6, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved:

xsk: validate MTU against usable frame size on bind

AFXDP bind currently accepts zero-copy pool configurations without verifying that the device MTU fits into the usable frame space provided by the UMEM chunk.

This becomes a problem since we started to respect tailroom which is subtracted from chunksize (among with headroom). 2k chunk size might not provide enough space for standard 1500 MTU, so let us catch such settings at bind time. Furthermore, validate whether underlying HW will be able to satisfy configured MTU wrt XSK's frame size multiplied by supported Rx buffer chain length (that is exposed via netdevice::xdpzcmaxsegs).

Affected Software

12 affected components

Linux Linux kernel

Linux Linux kernel>=6.6<6.6.136

Linux Linux kernel>=6.7<6.12.83

Linux Linux kernel>=6.13<6.18.24

Linux Linux kernel>=6.19<6.19.14

Linux Linux kernel=7.0-rc1

Linux Linux kernel=7.0-rc2

Linux Linux kernel=7.0-rc3

Linux Linux kernel=7.0-rc4

Linux Linux kernel=7.0-rc5

Linux Linux kernel=7.0-rc6

Linux Linux kernel=7.0-rc7

Remediation

Event History

May 6, 2026

CVE Published

via MITRE·07:40 AM

Data Sourced

via MITRE·07:40 AM

Description

Data Sourced

via NVD·10:16 AM

RemedyDescriptionSeverityAffected Software

Frequently Asked Questions

Who is exposed to this issue?

Systems using AF_XDP zero-copy pools are exposed when the device MTU exceeds the usable UMEM frame space after headroom and tailroom are deducted. Exposure can also depend on whether the hardware's supported receive-buffer chain length can accommodate the configured MTU.

What access does an attacker need?

The CVSS vector indicates local access and low privileges are required, with no user interaction. Exploitation involves binding an AF_XDP zero-copy pool using a frame-size configuration that cannot support the device MTU.

What is the impact?

The reported impact is availability only. The issue can lead to a high availability impact, while no confidentiality or integrity impact is indicated.

What should be done if affected?

Apply the available patch. Until patched, avoid binding AF_XDP zero-copy pools whose usable UMEM frame size, after headroom and tailroom, is smaller than the configured device MTU, and ensure the hardware's supported XSK receive-buffer chaining can satisfy that MTU.

CVE-2026-43092: xsk: validate MTU against usable frame size on bind

Affected Software

Remediation

Patch Available

Patch Available

Patch Available

Patch Available

Patch Available

Event History

Frequently Asked Questions

Who is exposed to this issue?

What access does an attacker need?

What is the impact?

What should be done if affected?

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Frequently Asked Questions

Who is exposed to this issue?

What access does an attacker need?

What is the impact?

What should be done if affected?