---
id: CVE-2026-72392
title: 'ipv6: fib6: fix NULL deref in fib6_walk_continue() on multi-batch dump'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: fib6: fix NULL deref in fib6_walk_continue() on multi-batch dump

  inet6_dump_fib() saves its progress in cb->args[1] as a positional
  index within the current hash…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    ee73a32dd258d4af66831ff006b771e19812b322
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    89f9c5fee3c64c5cabc34e65599308fd3c879cf9
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    cb90a774a9c6c46961a44949a246fbb61f5f934c
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    27210d433a8c5fe6bf7278a04bbaeb49a81d0290
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    059efb48dd746518898faaa9b965511009b59639
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    d8a01d27873e04bebd357dc87859aa756e0b28b2
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    110ccbd28c9444866fcc84ba96a2ad64fa6e95ae
  - >-
    Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 <
    9facb861dc6b9b9ea9793ef5032a9a826f7a4229
  - Linux 2.6.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:54:50.630136Z'
published: '2026-08-15'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:55:26.333Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-72392'
references:
  - url: 'https://git.kernel.org/stable/c/ee73a32dd258d4af66831ff006b771e19812b322'
  - url: 'https://git.kernel.org/stable/c/89f9c5fee3c64c5cabc34e65599308fd3c879cf9'
  - url: 'https://git.kernel.org/stable/c/cb90a774a9c6c46961a44949a246fbb61f5f934c'
  - url: 'https://git.kernel.org/stable/c/27210d433a8c5fe6bf7278a04bbaeb49a81d0290'
  - url: 'https://git.kernel.org/stable/c/059efb48dd746518898faaa9b965511009b59639'
  - url: 'https://git.kernel.org/stable/c/d8a01d27873e04bebd357dc87859aa756e0b28b2'
  - url: 'https://git.kernel.org/stable/c/110ccbd28c9444866fcc84ba96a2ad64fa6e95ae'
  - url: 'https://git.kernel.org/stable/c/9facb861dc6b9b9ea9793ef5032a9a826f7a4229'
tags:
  - cve.org
epss: 0.00216
epssPercentile: 0.12136
ingestedAt: '2026-11-06T18:00:12.578Z'
---

## Overview

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

ipv6: fib6: fix NULL deref in fib6_walk_continue() on multi-batch dump

inet6_dump_fib() saves its progress in cb->args[1] as a positional
index within the current hash chain.  Between batches, a concurrent
fib6_new_table() can insert a new table at the chain head, shifting
all existing entries.  The saved index then lands on a different
table, causing fib6_dump_table() to set w->root to the wrong table
while w->node still points into the previous one.
fib6_walk_continue() dereferences w->node->parent (NULL) and panics:

  BUG: kernel NULL pointer dereference, address: 0000000000000008
  RIP: 0010:fib6_walk_continue+0x6e/0x170
  Call Trace:
   <TASK>
   fib6_dump_table.isra.0+0xc5/0x240
   inet6_dump_fib+0xf6/0x420
   rtnl_dumpit+0x30/0xa0
   netlink_dump+0x15b/0x460
   netlink_recvmsg+0x1d6/0x2a0
   ____sys_recvmsg+0x17a/0x190

Fix by storing tb->tb6_id in cb->args[1] instead of a positional
index.  On resume, skip entries until the id matches; a concurrent
head-insert can never match the saved id, so the walker always
resumes on the correct table.

## Affected

- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < ee73a32dd258d4af66831ff006b771e19812b322`
- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < 89f9c5fee3c64c5cabc34e65599308fd3c879cf9`
- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < cb90a774a9c6c46961a44949a246fbb61f5f934c`
- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < 27210d433a8c5fe6bf7278a04bbaeb49a81d0290`
- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < 059efb48dd746518898faaa9b965511009b59639`
- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < d8a01d27873e04bebd357dc87859aa756e0b28b2`
- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < 110ccbd28c9444866fcc84ba96a2ad64fa6e95ae`
- `Linux >= 1b43af5480c351dbcb2eef478bafe179cbeb6e83 < 9facb861dc6b9b9ea9793ef5032a9a826f7a4229`
- `Linux 2.6.19`

## Remediation

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