---
id: CVE-2026-72436
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types

  Sashiko pointed out that there are a few lockless RCU readers
  using test_bit() which is a …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types

  Sashiko pointed out that there are a few lockless RCU readers
  using test_bit() which is a …
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-362
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:17:30.500'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72436'
references:
  - url: 'https://git.kernel.org/stable/c/3219d74e4536658c937fd878a327257b86ce80dd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6329d3a9afe715fddda0460cfa46b496d61c2fe0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7445fe965b7d8756070a40e80f8b73348ccda1d7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c107233d2ff4fd7cef5d02f9124b99194957a710'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c4d257734e91bfcdc71d41843392dd6400b5bb1b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e4b4984e28c16406ecb318444dea4a8bf47def3e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72436.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-72436'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2516356'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-72436'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-72436'
  - url: 'https://kernelcve.org/list/?q=CVE-2026-72436'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026081528-CVE-2026-72436-eb00@gregkh/T
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00712
epssPercentile: 0.53399
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T18:49:57.755944Z'
scores:
  nvd: 9.8
  vendor: 5.9
  cna: 9.8
ingestedAt: '2026-10-16T19:46:24.395Z'
---

## Overview

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

netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types

Sashiko pointed out that there are a few lockless RCU readers
using test_bit() which is a relaxed atomic operation and
provides no memory barrier guarantees. Use test_bit_acquire()
instead where the operation may run parallel with add/del/gc,
i.e. is not one from the next cases

- protected by region lock
- in a set destroy phase
- in a new/temporary set creation phase

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72436.json)