---
id: CVE-2026-53236
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tcp: restrict SO_ATTACH_FILTER to priv users

  This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets
  to users with CAP_NET_ADMIN capability.

  This block…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tcp: restrict SO_ATTACH_FILTER to priv users

  This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets
  to users with CAP_NET_ADMIN capability.

  This block…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 2.6.12.1, < 6.1.176'
  - 'linux_kernel >= 6.2, < 6.6.143'
  - 'linux_kernel >= 6.7, < 6.12.94'
  - 'linux_kernel >= 6.13, < 6.18.36'
  - 'linux_kernel >= 6.19, < 7.0.13'
  - linux_kernel = 2.6.12
  - linux_kernel = 7.1
patched:
  - linux_kernel 7.0.13
published: '2026-06-25'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:20:05.967'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53236'
references:
  - url: 'https://git.kernel.org/stable/c/3747de241a66ef2c7032d2cc2b826a47c5fa0f6a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5d39580f68e6ddeedd15e587282207489dfb3da2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/82b3e7ce10c53fc12aab8904745603efc74f8c07'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c68517a3e18e20997808821c5559d0cba4d776c1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ecfe9171b26ae3eed0cd8bab7a943e9e2c9e51ba'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ede69b8f6670600e534591664584f810d7c385f9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-457936.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53236.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-53236'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492709'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-53236'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53236'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026062510-CVE-2026-53236-45bc@gregkh/T
  - url: 'https://access.redhat.com/errata/RHSA-2026:89083'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00125
epssPercentile: 0.02211
ingestedAt: '2026-09-08T13:33:25.832Z'
cwe:
  - CWE-266
scores:
  nvd: 5.5
  vendor: 7.1
---

## Overview

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

tcp: restrict SO_ATTACH_FILTER to priv users

This patch restricts the use of SO_ATTACH_FILTER (cBPF) on TCP sockets
to users with CAP_NET_ADMIN capability.

This blocks potential side-channel attack where an unprivileged application
attaches a filter to leak TCP sequence/acknowledgment numbers.

## Affected

- `linux_kernel >= 2.6.12.1, < 6.1.176`
- `linux_kernel >= 6.2, < 6.6.143`
- `linux_kernel >= 6.7, < 6.12.94`
- `linux_kernel >= 6.13, < 6.18.36`
- `linux_kernel >= 6.19, < 7.0.13`
- `linux_kernel = 2.6.12`
- `linux_kernel = 7.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.13`

## Vendor advisories

- **RHSA-2026:89083** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:89083)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53236.json)