---
id: CVE-2025-40018
title: 'ipvs: Defer ip_vs_ftp unregister during netns cleanup'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipvs: Defer ip_vs_ftp unregister during netns cleanup

  On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp
  before connections with valid cp->app poin…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    8a6ecab3847c213ce2855b0378e63ce839085de3
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    421b1ae1574dfdda68b835c15ac4921ec0030182
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    1d79471414d7b9424d699afff2aa79fff322f52d
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    53717f8a4347b78eac6488072ad8e5adbaff38d9
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    8cbe2a21d85727b66d7c591fd5d83df0d8c4f757
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    dc1a481359a72ee7e548f1f5da671282a7c13b8f
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    a343811ef138a265407167294275201621e9ebb2
  - >-
    Linux >= 61b1ab4583e275af216c8454b9256de680499b19 <
    134121bfd99a06d44ef5ba15a9beb075297c0821
  - Linux 2.6.39
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:56:10.486457Z'
published: '2025-10-24'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:02:36.226Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-40018'
references:
  - url: 'https://git.kernel.org/stable/c/8a6ecab3847c213ce2855b0378e63ce839085de3'
  - url: 'https://git.kernel.org/stable/c/421b1ae1574dfdda68b835c15ac4921ec0030182'
  - url: 'https://git.kernel.org/stable/c/1d79471414d7b9424d699afff2aa79fff322f52d'
  - url: 'https://git.kernel.org/stable/c/53717f8a4347b78eac6488072ad8e5adbaff38d9'
  - url: 'https://git.kernel.org/stable/c/8cbe2a21d85727b66d7c591fd5d83df0d8c4f757'
  - url: 'https://git.kernel.org/stable/c/dc1a481359a72ee7e548f1f5da671282a7c13b8f'
  - url: 'https://git.kernel.org/stable/c/a343811ef138a265407167294275201621e9ebb2'
  - url: 'https://git.kernel.org/stable/c/134121bfd99a06d44ef5ba15a9beb075297c0821'
tags:
  - cve.org
epss: 0.0015
epssPercentile: 0.04134
ingestedAt: '2026-10-15T22:48:25.538Z'
---

## Overview

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

ipvs: Defer ip_vs_ftp unregister during netns cleanup

On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp
before connections with valid cp->app pointers are flushed, leading to a
use-after-free.

Fix this by introducing a global `exiting_module` flag, set to true in
ip_vs_ftp_exit() before unregistering the pernet subsystem. In
__ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns
cleanup (when exiting_module is false) and defer it to
__ip_vs_cleanup_batch(), which unregisters all apps after all connections
are flushed. If called during module exit, unregister ip_vs_ftp
immediately.

## Affected

- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < 8a6ecab3847c213ce2855b0378e63ce839085de3`
- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < 421b1ae1574dfdda68b835c15ac4921ec0030182`
- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < 1d79471414d7b9424d699afff2aa79fff322f52d`
- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < 53717f8a4347b78eac6488072ad8e5adbaff38d9`
- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < 8cbe2a21d85727b66d7c591fd5d83df0d8c4f757`
- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < dc1a481359a72ee7e548f1f5da671282a7c13b8f`
- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < a343811ef138a265407167294275201621e9ebb2`
- `Linux >= 61b1ab4583e275af216c8454b9256de680499b19 < 134121bfd99a06d44ef5ba15a9beb075297c0821`
- `Linux 2.6.39`

## Remediation

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