---
id: CVE-2025-21669
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  vsock/virtio: discard packets if the transport changes

  If the socket has been de-assigned or assigned to another transport,
  we must discard any packets received becaus…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  vsock/virtio: discard packets if the transport changes

  If the socket has been de-assigned or assigned to another transport,
  we must discard any packets received becaus…
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'
cwe:
  - CWE-476
  - CWE-476
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.5, < 5.15.177'
  - 'linux_kernel >= 5.16, < 6.1.127'
  - 'linux_kernel >= 6.2, < 6.6.74'
  - 'linux_kernel >= 6.7, < 6.12.11'
  - linux_kernel = 6.13
patched:
  - linux_kernel 6.12.11
published: '2025-01-31'
updated: '2026-07-30'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-21669'
references:
  - url: 'https://git.kernel.org/stable/c/18a7fc371d1dbf8deff16c2dd9292bcc73f43040'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2cb7c756f605ec02ffe562fb26828e4bcc5fdfc1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6486915fa661584d70e8e7e4068c6c075c67dd6d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/677579b641af109613564460a4e3bdcb16850b61'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/88244163bc7e7b0ce9dd7bf4c8a563b41525c3ee'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d88b249e14bd0ee1e46bbe4f456e22e01b8c68de'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-265688.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.00234
epssPercentile: 0.12684
ingestedAt: '2026-07-30T06:53:09.103Z'
---

## Overview

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

vsock/virtio: discard packets if the transport changes

If the socket has been de-assigned or assigned to another transport,
we must discard any packets received because they are not expected
and would cause issues when we access vsk->transport.

A possible scenario is described by Hyunwoo Kim in the attached link,
where after a first connect() interrupted by a signal, and a second
connect() failed, we can find `vsk->transport` at NULL, leading to a
NULL pointer dereference.

## Affected

- `linux_kernel >= 5.5, < 5.15.177`
- `linux_kernel >= 5.16, < 6.1.127`
- `linux_kernel >= 6.2, < 6.6.74`
- `linux_kernel >= 6.7, < 6.12.11`
- `linux_kernel = 6.13`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.12.11`