---
id: CVE-2026-80584
title: 's390/qeth: validate user buffer length in SNMP and ARP query ioctls'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/qeth: validate user buffer length in SNMP and ARP query ioctls

  qeth_snmp_command() and qeth_l3_arp_query() allocate a buffer sized by
  a user-supplied length (udat…
severity: high
cvss: 8.4
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    9d00eeb2d27f4cc817c5e408760226d43f811ec6
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    46443eaddebd84c51940857b11787229be169dec
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    91935843f9396a9e45253e2c0d4337ca1371754b
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    cc423f4105fe145b33e1d7cad34245a798358f73
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    3083818e67bcd656965797fbac9a3d6c1d44f78a
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    a3083647747942ea32faf14560d6397ff3068046
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    75fb3151513d7d9f77a8f9545418279b119c06b8
  - >-
    Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba <
    d141f087b1af656f055d7c5793a3e87817ba0bbe
  - Linux 2.6.26
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T19:17:53.198738Z'
published: '2026-08-26'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:26:28.329Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80584'
references:
  - url: 'https://git.kernel.org/stable/c/9d00eeb2d27f4cc817c5e408760226d43f811ec6'
  - url: 'https://git.kernel.org/stable/c/46443eaddebd84c51940857b11787229be169dec'
  - url: 'https://git.kernel.org/stable/c/91935843f9396a9e45253e2c0d4337ca1371754b'
  - url: 'https://git.kernel.org/stable/c/cc423f4105fe145b33e1d7cad34245a798358f73'
  - url: 'https://git.kernel.org/stable/c/3083818e67bcd656965797fbac9a3d6c1d44f78a'
  - url: 'https://git.kernel.org/stable/c/a3083647747942ea32faf14560d6397ff3068046'
  - url: 'https://git.kernel.org/stable/c/75fb3151513d7d9f77a8f9545418279b119c06b8'
  - url: 'https://git.kernel.org/stable/c/d141f087b1af656f055d7c5793a3e87817ba0bbe'
tags:
  - cve.org
epss: 0.00196
epssPercentile: 0.08646
ingestedAt: '2026-10-16T19:46:24.311Z'
---

## Overview

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

s390/qeth: validate user buffer length in SNMP and ARP query ioctls

qeth_snmp_command() and qeth_l3_arp_query() allocate a buffer sized by
a user-supplied length (udata_len) without checking a lower bound, then
set udata_offset to a fixed non-zero value and pass both to a reply
callback. The callback bounds-checks the copy with

        if ((udata_len - udata_offset) < len)

Both fields are u32, so a udata_len smaller than udata_offset makes the
subtraction wrap and the check pass, and the following memcpy() writes
past the allocation. A udata_len of 0 also yields ZERO_SIZE_PTR from
kzalloc(), which the existing NULL check does not catch.

Reject buffers smaller than udata_offset before allocating, so the
callback subtraction can no longer underflow.

## Affected

- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < 9d00eeb2d27f4cc817c5e408760226d43f811ec6`
- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < 46443eaddebd84c51940857b11787229be169dec`
- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < 91935843f9396a9e45253e2c0d4337ca1371754b`
- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < cc423f4105fe145b33e1d7cad34245a798358f73`
- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < 3083818e67bcd656965797fbac9a3d6c1d44f78a`
- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < a3083647747942ea32faf14560d6397ff3068046`
- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < 75fb3151513d7d9f77a8f9545418279b119c06b8`
- `Linux >= 4a71df50047f0db65ea09b1be155852e81a45eba < d141f087b1af656f055d7c5793a3e87817ba0bbe`
- `Linux 2.6.26`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.