---
id: CVE-2026-53075
title: 'ppp: require CAP_NET_ADMIN in target netns for unattached ioctls'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ppp: require CAP_NET_ADMIN in target netns for unattached ioctls

  /dev/ppp open is currently authorized against file->f_cred->user_ns,
  while unattached administrative i…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    c9edd90c57ae23692fff6b049fdfa4572a9fd532
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    5080e188c914110034bbc569d5cfa2f06204681d
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    67e901e28d177ac9a9bed76d69ce3471e704a89e
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    954745d0223e7caec917c0b2d1a889ff56fa6e54
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    3b2c2157dc2afc5c17cd7238afefca92f1ef330e
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    5013be175c7ffd8b39efbc3c9c4db5b10b85fea8
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    1a8a51ce85075a56a743b6f142606dd2696a391c
  - >-
    Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e <
    2bb6379416fd19f44c3423a00bfd8626259f6067
  - Linux 2.6.30
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:25:15.108813Z'
exploitAvailable: true
published: '2026-06-24'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:31:30.854Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-53075'
references:
  - url: 'https://git.kernel.org/stable/c/c9edd90c57ae23692fff6b049fdfa4572a9fd532'
  - url: 'https://git.kernel.org/stable/c/5080e188c914110034bbc569d5cfa2f06204681d'
  - url: 'https://git.kernel.org/stable/c/67e901e28d177ac9a9bed76d69ce3471e704a89e'
  - url: 'https://git.kernel.org/stable/c/954745d0223e7caec917c0b2d1a889ff56fa6e54'
  - url: 'https://git.kernel.org/stable/c/3b2c2157dc2afc5c17cd7238afefca92f1ef330e'
  - url: 'https://git.kernel.org/stable/c/5013be175c7ffd8b39efbc3c9c4db5b10b85fea8'
  - url: 'https://git.kernel.org/stable/c/1a8a51ce85075a56a743b6f142606dd2696a391c'
  - url: 'https://git.kernel.org/stable/c/2bb6379416fd19f44c3423a00bfd8626259f6067'
tags:
  - cve.org
  - exploit-available
epss: 0.0025
epssPercentile: 0.15248
exploits:
  github: 2
  githubRepos:
    - 'https://github.com/foxirain/linux-kernel-codex-harness-v2'
    - 'https://github.com/lottiedeyan/CVE-2026-53075poc'
  checkedAt: '2026-10-16T17:25:21.012Z'
ingestedAt: '2026-10-16T17:24:46.729Z'
---

## Overview

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

ppp: require CAP_NET_ADMIN in target netns for unattached ioctls

/dev/ppp open is currently authorized against file->f_cred->user_ns,
while unattached administrative ioctls operate on current->nsproxy->net_ns.

As a result, a local unprivileged user can create a new user namespace
with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace,
and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against
an inherited network namespace.

Require CAP_NET_ADMIN in the user namespace that owns the target network
namespace before handling unattached PPP administrative ioctls.

This preserves normal pppd operation in the network namespace it is
actually privileged in, while rejecting the userns-only inherited-netns
case.

## Affected

- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < c9edd90c57ae23692fff6b049fdfa4572a9fd532`
- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < 5080e188c914110034bbc569d5cfa2f06204681d`
- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < 67e901e28d177ac9a9bed76d69ce3471e704a89e`
- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < 954745d0223e7caec917c0b2d1a889ff56fa6e54`
- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < 3b2c2157dc2afc5c17cd7238afefca92f1ef330e`
- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < 5013be175c7ffd8b39efbc3c9c4db5b10b85fea8`
- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < 1a8a51ce85075a56a743b6f142606dd2696a391c`
- `Linux >= 273ec51dd7ceaa76e038875d85061ec856d8905e < 2bb6379416fd19f44c3423a00bfd8626259f6067`
- `Linux 2.6.30`

## Remediation

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