---
id: CVE-2026-99071
title: 'ipv4: do not warn on route notification size race'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv4: do not warn on route notification size race

  Commit 680aea08e78c ("net: ipv4: Emit notification when fib hardware
  flags are changed") added asynchronous route not…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 <
    088ba80eef85fa7a5ad8f9e7c82b403c99242b56
  - >-
    Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 <
    78a1cf5c54b2f795c81fedb530755a8d01cc84f0
  - >-
    Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 <
    7dfa7ca97f3ac46353edd4cc44f7733758e4535b
  - >-
    Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 <
    221ef5e1e44a044790f0f54e6aa237883f475a4d
  - >-
    Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 <
    e02a5b6588161673ef75a4bc5cdfb62bd493374d
  - Linux 5.12
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T12:23:14.297Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99071'
references:
  - url: 'https://git.kernel.org/stable/c/088ba80eef85fa7a5ad8f9e7c82b403c99242b56'
  - url: 'https://git.kernel.org/stable/c/78a1cf5c54b2f795c81fedb530755a8d01cc84f0'
  - url: 'https://git.kernel.org/stable/c/7dfa7ca97f3ac46353edd4cc44f7733758e4535b'
  - url: 'https://git.kernel.org/stable/c/221ef5e1e44a044790f0f54e6aa237883f475a4d'
  - url: 'https://git.kernel.org/stable/c/e02a5b6588161673ef75a4bc5cdfb62bd493374d'
tags:
  - cve.org
ingestedAt: '2026-10-23T13:24:55.515Z'
---

## Overview

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

ipv4: do not warn on route notification size race

Commit 680aea08e78c ("net: ipv4: Emit notification when fib hardware
flags are changed") added asynchronous route notifications for hardware
flag changes.

fib_alias_hw_flags_set() sizes the skb with fib_nlmsg_size() and later
fills it with fib_dump_info() while holding only RCU.  With nexthop
compatibility mode enabled, a concurrent replacement can grow the group
between these independent snapshots.  fib_dump_info() can then
legitimately return -EMSGSIZE, so the warning does not prove a sizing bug.

Remove the warning.  The existing error path still frees the skb and
reports the error to listeners.

## Affected

- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < 088ba80eef85fa7a5ad8f9e7c82b403c99242b56`
- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < 78a1cf5c54b2f795c81fedb530755a8d01cc84f0`
- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < 7dfa7ca97f3ac46353edd4cc44f7733758e4535b`
- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < 221ef5e1e44a044790f0f54e6aa237883f475a4d`
- `Linux >= 680aea08e78c003292415518ad270bc20f9c80b1 < e02a5b6588161673ef75a4bc5cdfb62bd493374d`
- `Linux 5.12`

## Remediation

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