---
id: CVE-2025-21764
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ndisc: use RCU protection in ndisc_alloc_skb()

  ndisc_alloc_skb() can be called without RTNL or RCU being held.

  Add RCU protection to avoid possible UAF.
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ndisc: use RCU protection in ndisc_alloc_skb()

  ndisc_alloc_skb() can be called without RTNL or RCU being held.

  Add RCU protection to avoid possible UAF.
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-416
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 3.9, < 5.4.291'
  - 'linux_kernel >= 5.5, < 5.10.235'
  - 'linux_kernel >= 5.11, < 5.15.179'
  - 'linux_kernel >= 5.16, < 6.1.129'
  - 'linux_kernel >= 6.2, < 6.6.79'
  - 'linux_kernel >= 6.7, < 6.12.16'
  - 'linux_kernel >= 6.13, < 6.13.4'
  - linux_kernel = 6.14
patched:
  - linux_kernel 6.13.4
published: '2025-02-27'
updated: '2026-07-14'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-21764'
references:
  - url: 'https://git.kernel.org/stable/c/3c2d705f5adf5d860aaef90cb4211c0fde2ba66d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/628e6d18930bbd21f2d4562228afe27694f66da9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/96fc896d0e5b37c12808df797397fb16f3080879'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9e0ec817eb41a55327a46cd3ce331a9868d60304'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b870256dd2a5648d5ed2f22316b3ac29a7e5ed63'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bbec88e4108e8d6fb468d3817fa652140a44ff28'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c30893ef3d9cde8e7e8e4fd06b53d2c935bbccb1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cd1065f92eb7ff21b9ba5308a86f33d1670bf926'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-265688.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00261
epssPercentile: 0.18145
ingestedAt: '2026-07-14T13:36:55.678Z'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2025-02-27T17:57:20.278381Z'
---

## Overview

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

ndisc: use RCU protection in ndisc_alloc_skb()

ndisc_alloc_skb() can be called without RTNL or RCU being held.

Add RCU protection to avoid possible UAF.

## Affected

- `linux_kernel >= 3.9, < 5.4.291`
- `linux_kernel >= 5.5, < 5.10.235`
- `linux_kernel >= 5.11, < 5.15.179`
- `linux_kernel >= 5.16, < 6.1.129`
- `linux_kernel >= 6.2, < 6.6.79`
- `linux_kernel >= 6.7, < 6.12.16`
- `linux_kernel >= 6.13, < 6.13.4`
- `linux_kernel = 6.14`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.13.4`