---
id: CVE-2026-52925
title: 'vrf: Fix a potential NPD when removing a port from a VRF'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  vrf: Fix a potential NPD when removing a port from a VRF

  RCU readers that identified a net device as a VRF port using
  netif_is_l3_slave() assume that a subsequent call…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    2c022f582fd16a470df6ed9e7fb7e9fc48946d49
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    4ab6fc60ed5a0344b60711b09bff1dc238d8d6a4
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    468defa0b70902a22f4478c1207624bc1b31c124
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    3db8d078f7f652379ee394132b169d304f6eb4c1
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    8c2b792f04a3db97c9d8d2a45817e93f8884baf5
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    a7a97f2303e63ede105c1d55ef53dc497364e11d
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    d47204c127992da0c976ac9747070a575912e0fe
  - >-
    Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 <
    2674d603a9e6970463b2b9ebcf8e31e90beae169
  - Linux 4.12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:14:10.024799Z'
published: '2026-06-24'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:23:49.718Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-52925'
references:
  - url: 'https://git.kernel.org/stable/c/2c022f582fd16a470df6ed9e7fb7e9fc48946d49'
  - url: 'https://git.kernel.org/stable/c/4ab6fc60ed5a0344b60711b09bff1dc238d8d6a4'
  - url: 'https://git.kernel.org/stable/c/468defa0b70902a22f4478c1207624bc1b31c124'
  - url: 'https://git.kernel.org/stable/c/3db8d078f7f652379ee394132b169d304f6eb4c1'
  - url: 'https://git.kernel.org/stable/c/8c2b792f04a3db97c9d8d2a45817e93f8884baf5'
  - url: 'https://git.kernel.org/stable/c/a7a97f2303e63ede105c1d55ef53dc497364e11d'
  - url: 'https://git.kernel.org/stable/c/d47204c127992da0c976ac9747070a575912e0fe'
  - url: 'https://git.kernel.org/stable/c/2674d603a9e6970463b2b9ebcf8e31e90beae169'
tags:
  - cve.org
epss: 0.00114
epssPercentile: 0.01503
ingestedAt: '2026-11-06T16:57:43.311Z'
---

## Overview

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

vrf: Fix a potential NPD when removing a port from a VRF

RCU readers that identified a net device as a VRF port using
netif_is_l3_slave() assume that a subsequent call to
netdev_master_upper_dev_get_rcu() will return a VRF device. They then
continue to dereference its l3mdev operations.

This assumption is not always correct and can result in a NPD [1]. There
is no RCU synchronization when removing a port from a VRF, so it is
possible for an RCU reader to see a new master device (e.g., a bridge)
that does not have l3mdev operations.

Fix by adding RCU synchronization after clearing the IFF_L3MDEV_SLAVE
flag. Skip this synchronization when a net device is removed from a VRF
as part of its deletion and when the VRF device itself is deleted. In
the latter case an RCU grace period will pass by the time RTNL is
released.

[1]
BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
RIP: 0010:l3mdev_fib_table_rcu (net/l3mdev/l3mdev.c:181)
[...]
Call Trace:
<TASK>
l3mdev_fib_table_by_index (net/l3mdev/l3mdev.c:201 net/l3mdev/l3mdev.c:189)
__inet_bind (net/ipv4/af_inet.c:499 (discriminator 3))
inet_bind_sk (net/ipv4/af_inet.c:469)
__sys_bind (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:1951 (discriminator 1))
__x64_sys_bind (net/socket.c:1969 (discriminator 1) net/socket.c:1967 (discriminator 1) net/socket.c:1967 (discriminator 1))
do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

## Affected

- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < 2c022f582fd16a470df6ed9e7fb7e9fc48946d49`
- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < 4ab6fc60ed5a0344b60711b09bff1dc238d8d6a4`
- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < 468defa0b70902a22f4478c1207624bc1b31c124`
- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < 3db8d078f7f652379ee394132b169d304f6eb4c1`
- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < 8c2b792f04a3db97c9d8d2a45817e93f8884baf5`
- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < a7a97f2303e63ede105c1d55ef53dc497364e11d`
- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < d47204c127992da0c976ac9747070a575912e0fe`
- `Linux >= fdeea7be88b12742bfd50d9e19a06c0d2e702400 < 2674d603a9e6970463b2b9ebcf8e31e90beae169`
- `Linux 4.12`

## Remediation

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