---
id: CVE-2026-63919
title: 'xfrm: input: hold netns during deferred transport reinjection'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  xfrm: input: hold netns during deferred transport reinjection

  Transport-mode reinjection stores a struct net pointer in skb->cb and
  uses it later from xfrm_trans_reinj…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    7ee59eda8820b758ed29e1cd3222359c7b97302c
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    2df7059a18afb7d3aee6c36cad5d371c198111d4
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    8dfabcba6a943a7a02ebe1e1637c361ba96acbaa
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    48ce101cd630d6745b6923b5bad8358bc4c119da
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    55ddfc41451f01c588089cd74957a05311b6f202
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    9f7ebb45a83afc3216e855e57d51bb4bc9b5232e
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    9f67a36e91bb50d358760f381f233913fe5c09f8
  - >-
    Linux >= 7b3801927e52f8621de311277f7fc727635019e7 <
    c16f74dc1d75d0e2e7670076d5375deda110ebeb
  - Linux 5.6
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:33:20.958476Z'
published: '2026-07-19'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:42:11.562Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63919'
references:
  - url: 'https://git.kernel.org/stable/c/7ee59eda8820b758ed29e1cd3222359c7b97302c'
  - url: 'https://git.kernel.org/stable/c/2df7059a18afb7d3aee6c36cad5d371c198111d4'
  - url: 'https://git.kernel.org/stable/c/8dfabcba6a943a7a02ebe1e1637c361ba96acbaa'
  - url: 'https://git.kernel.org/stable/c/48ce101cd630d6745b6923b5bad8358bc4c119da'
  - url: 'https://git.kernel.org/stable/c/55ddfc41451f01c588089cd74957a05311b6f202'
  - url: 'https://git.kernel.org/stable/c/9f7ebb45a83afc3216e855e57d51bb4bc9b5232e'
  - url: 'https://git.kernel.org/stable/c/9f67a36e91bb50d358760f381f233913fe5c09f8'
  - url: 'https://git.kernel.org/stable/c/c16f74dc1d75d0e2e7670076d5375deda110ebeb'
tags:
  - cve.org
epss: 0.0065
epssPercentile: 0.50124
ingestedAt: '2026-10-16T17:24:46.776Z'
---

## Overview

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

xfrm: input: hold netns during deferred transport reinjection

Transport-mode reinjection stores a struct net pointer in skb->cb and
uses it later from xfrm_trans_reinject(). That pointer must stay valid
until the deferred callback runs.

Take a netns reference when queueing deferred reinjection work and drop
it after the callback completes. Use maybe_get_net() so the queueing
path does not revive a namespace that is already being torn down.

This keeps the existing workqueue design and fixes the netns lifetime
handling in one place for all users of xfrm_trans_queue_net().

## Affected

- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < 7ee59eda8820b758ed29e1cd3222359c7b97302c`
- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < 2df7059a18afb7d3aee6c36cad5d371c198111d4`
- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < 8dfabcba6a943a7a02ebe1e1637c361ba96acbaa`
- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < 48ce101cd630d6745b6923b5bad8358bc4c119da`
- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < 55ddfc41451f01c588089cd74957a05311b6f202`
- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < 9f7ebb45a83afc3216e855e57d51bb4bc9b5232e`
- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < 9f67a36e91bb50d358760f381f233913fe5c09f8`
- `Linux >= 7b3801927e52f8621de311277f7fc727635019e7 < c16f74dc1d75d0e2e7670076d5375deda110ebeb`
- `Linux 5.6`

## Remediation

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