---
id: CVE-2025-21637
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sctp: sysctl: udp_port: avoid using current->nsproxy

  As mentioned in a previous commit of this series, using the 'net'
  structure via 'current' is not recommended for d…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sctp: sysctl: udp_port: avoid using current->nsproxy

  As mentioned in a previous commit of this series, using the 'net'
  structure via 'current' is not recommended for d…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'
cwe:
  - CWE-476
  - CWE-476
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.11, < 5.15.177'
  - 'linux_kernel >= 5.16, < 6.1.125'
  - 'linux_kernel >= 6.2, < 6.6.72'
  - 'linux_kernel >= 6.7, < 6.12.10'
  - linux_kernel = 6.13
patched:
  - linux_kernel 6.12.10
published: '2025-01-19'
updated: '2026-07-30'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-21637'
references:
  - url: 'https://git.kernel.org/stable/c/0a0966312ac3eedd7f5f2a766ed4702df39a9a65'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/55627918febdf9d71107a1e68d1528dc591c9a15'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5b77d73f3be5102720fb685b9e6900e3500e1096'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c10377bbc1972d858eaf0ab366a311b39f8ef1b6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e919197fb8616331f5dc81e4c3cc3d12769cb725'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00213
epssPercentile: 0.10303
ingestedAt: '2026-07-30T06:53:08.824Z'
---

## Overview

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

sctp: sysctl: udp_port: avoid using current->nsproxy

As mentioned in a previous commit of this series, using the 'net'
structure via 'current' is not recommended for different reasons:

- Inconsistency: getting info from the reader's/writer's netns vs only
  from the opener's netns.

- current->nsproxy can be NULL in some cases, resulting in an 'Oops'
  (null-ptr-deref), e.g. when the current task is exiting, as spotted by
  syzbot [1] using acct(2).

The 'net' structure can be obtained from the table->data using
container_of().

Note that table->data could also be used directly, but that would
increase the size of this fix, while 'sctp.ctl_sock' still needs to be
retrieved from 'net' structure.

## Affected

- `linux_kernel >= 5.11, < 5.15.177`
- `linux_kernel >= 5.16, < 6.1.125`
- `linux_kernel >= 6.2, < 6.6.72`
- `linux_kernel >= 6.7, < 6.12.10`
- `linux_kernel = 6.13`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.12.10`