---
id: CVE-2026-72297
title: 'net: atm: reject out-of-range traffic classes in QoS validation'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: atm: reject out-of-range traffic classes in QoS validation

  Reject ATM traffic classes above ATM_ANYCLASS in check_tp().
  SO_ATMQOS stores the supplied QoS after ch…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    1a6dda72455b399ce9c1a12695471dc4d5c61add
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    2b3e241729e87afed13ac0f666472d5d6ca42e87
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    367acd288bc6255e247cb1a1efbf5c6567cab423
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    513f820b3f0cf4462e17d84c39ed3948d061a6ea
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    15444b57fdc6fc3f3e22a87f791ae5be81e6ecf5
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    e62adb157c2eaad9ad4867ec6cd9af5b9a51b1c7
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    806b7b6edc8446e8b94b706807a7090a14d47b5c
  - >-
    Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <
    cdf19f380e46192e7084be559638aab1f6ed86a2
  - Linux 2.6.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-16T18:45:57.327476Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T18:55:15.534Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72297'
references:
  - url: 'https://git.kernel.org/stable/c/1a6dda72455b399ce9c1a12695471dc4d5c61add'
  - url: 'https://git.kernel.org/stable/c/2b3e241729e87afed13ac0f666472d5d6ca42e87'
  - url: 'https://git.kernel.org/stable/c/367acd288bc6255e247cb1a1efbf5c6567cab423'
  - url: 'https://git.kernel.org/stable/c/513f820b3f0cf4462e17d84c39ed3948d061a6ea'
  - url: 'https://git.kernel.org/stable/c/15444b57fdc6fc3f3e22a87f791ae5be81e6ecf5'
  - url: 'https://git.kernel.org/stable/c/e62adb157c2eaad9ad4867ec6cd9af5b9a51b1c7'
  - url: 'https://git.kernel.org/stable/c/806b7b6edc8446e8b94b706807a7090a14d47b5c'
  - url: 'https://git.kernel.org/stable/c/cdf19f380e46192e7084be559638aab1f6ed86a2'
tags:
  - cve.org
epss: 0.00164
epssPercentile: 0.05252
ingestedAt: '2026-10-16T19:46:24.411Z'
---

## Overview

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

net: atm: reject out-of-range traffic classes in QoS validation

Reject ATM traffic classes above ATM_ANYCLASS in check_tp().
SO_ATMQOS stores the supplied QoS after check_qos() succeeds, so
accepting larger values leaves invalid traffic_class values in
vcc->qos.

That bad state later reaches pvc_info(), which indexes class_name[]
with vcc->qos.{rx,tp}.traffic_class. Values above ATM_ANYCLASS cause
an out-of-bounds read when /proc/net/atm/pvc is read.

Tighten the existing QoS validation so invalid traffic_class values
are rejected at the point where user supplied QoS is accepted.

## Affected

- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1a6dda72455b399ce9c1a12695471dc4d5c61add`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2b3e241729e87afed13ac0f666472d5d6ca42e87`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 367acd288bc6255e247cb1a1efbf5c6567cab423`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 513f820b3f0cf4462e17d84c39ed3948d061a6ea`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 15444b57fdc6fc3f3e22a87f791ae5be81e6ecf5`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e62adb157c2eaad9ad4867ec6cd9af5b9a51b1c7`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 806b7b6edc8446e8b94b706807a7090a14d47b5c`
- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < cdf19f380e46192e7084be559638aab1f6ed86a2`
- `Linux 2.6.12`

## Remediation

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