---
id: CVE-2026-43238
title: 'net/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()

  Commit 38a6f0865796 ("net: sched: support hash selecting tx queue")
  added SKBEDIT_F_TXQ_SKBHASH suppor…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f <
    59809fda4da7730cfe84a948033f47eb45db073d
  - >-
    Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f <
    9c735a7d98c982a786b0db71eb6566ee00aaa04f
  - >-
    Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f <
    015cebdfcb97b5347fb7f598ea712a281cb35840
  - >-
    Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f <
    4ece5eb4836f8ff03b9004dc2430a7169f282851
  - >-
    Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f <
    3c2b95b26860bd6f8e2310d31ea1200d3f8f173e
  - >-
    Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f <
    be054cc66f739a9ba615dba9012a07fab8e7dd6f
  - Linux 5.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T15:31:06.549256Z'
published: '2026-05-06'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T15:32:36.828Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43238'
references:
  - url: 'https://git.kernel.org/stable/c/59809fda4da7730cfe84a948033f47eb45db073d'
  - url: 'https://git.kernel.org/stable/c/9c735a7d98c982a786b0db71eb6566ee00aaa04f'
  - url: 'https://git.kernel.org/stable/c/015cebdfcb97b5347fb7f598ea712a281cb35840'
  - url: 'https://git.kernel.org/stable/c/4ece5eb4836f8ff03b9004dc2430a7169f282851'
  - url: 'https://git.kernel.org/stable/c/3c2b95b26860bd6f8e2310d31ea1200d3f8f173e'
  - url: 'https://git.kernel.org/stable/c/be054cc66f739a9ba615dba9012a07fab8e7dd6f'
tags:
  - cve.org
epss: 0.00128
epssPercentile: 0.02474
ingestedAt: '2026-11-06T15:54:04.006Z'
---

## Overview

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

net/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()

Commit 38a6f0865796 ("net: sched: support hash selecting tx queue")
added SKBEDIT_F_TXQ_SKBHASH support. The inclusive range size is
computed as:

mapping_mod = queue_mapping_max - queue_mapping + 1;

The range size can be 65536 when the requested range covers all possible
u16 queue IDs (e.g. queue_mapping=0 and queue_mapping_max=U16_MAX).
That value cannot be represented in a u16 and previously wrapped to 0,
so tcf_skbedit_hash() could trigger a divide-by-zero:

queue_mapping += skb_get_hash(skb) % params->mapping_mod;

Compute mapping_mod in a wider type and reject ranges larger than U16_MAX
to prevent params->mapping_mod from becoming 0 and avoid the crash.

## Affected

- `Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f < 59809fda4da7730cfe84a948033f47eb45db073d`
- `Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f < 9c735a7d98c982a786b0db71eb6566ee00aaa04f`
- `Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f < 015cebdfcb97b5347fb7f598ea712a281cb35840`
- `Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f < 4ece5eb4836f8ff03b9004dc2430a7169f282851`
- `Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f < 3c2b95b26860bd6f8e2310d31ea1200d3f8f173e`
- `Linux >= 38a6f0865796e26fc38fff4858f681d9ae76fa0f < be054cc66f739a9ba615dba9012a07fab8e7dd6f`
- `Linux 5.19`

## Remediation

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