---
id: CVE-2026-74398
title: 'ipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD

  addrconf_dad_failure() transitions ifp->state from DAD to POSTDAD
  via addrconf_dad_end(), which…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    47b05836705b63dab93d9ac7c69a3a507375ef80
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    d21be7d051012c6b572fa4e3334443c250216f7b
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    875c284c0f98b042bb97abad460f63a24c977f88
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    8ed0ce9ea58d677d1bac92614ee5f60f8ea57363
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    b61af0268e3d1308c466bf0be5dced844eafc1ef
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    e889aa99ad3ed48bb0ddcff6475b17542532d18b
  - >-
    Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 <
    627ac78f2741e2ebd2225e2e953b6964a8a9182f
  - Linux 835b474b8f70fa68d68abffad37378e92f661802
  - Linux >= 3.10.105 < 3.11
  - Linux 3.14
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T18:55:29.102774Z'
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T19:05:41.331Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74398'
references:
  - url: 'https://git.kernel.org/stable/c/47b05836705b63dab93d9ac7c69a3a507375ef80'
  - url: 'https://git.kernel.org/stable/c/d21be7d051012c6b572fa4e3334443c250216f7b'
  - url: 'https://git.kernel.org/stable/c/875c284c0f98b042bb97abad460f63a24c977f88'
  - url: 'https://git.kernel.org/stable/c/8ed0ce9ea58d677d1bac92614ee5f60f8ea57363'
  - url: 'https://git.kernel.org/stable/c/3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb'
  - url: 'https://git.kernel.org/stable/c/b61af0268e3d1308c466bf0be5dced844eafc1ef'
  - url: 'https://git.kernel.org/stable/c/e889aa99ad3ed48bb0ddcff6475b17542532d18b'
  - url: 'https://git.kernel.org/stable/c/627ac78f2741e2ebd2225e2e953b6964a8a9182f'
tags:
  - cve.org
epss: 0.00514
epssPercentile: 0.42496
ingestedAt: '2026-10-16T19:46:24.368Z'
---

## Overview

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

ipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD

addrconf_dad_failure() transitions ifp->state from DAD to POSTDAD
via addrconf_dad_end(), which drops ifp->lock on return.  The lock
is re-acquired after net_info_ratelimited().  A concurrent
ipv6_del_addr() can take the lock in that window, set ifp->state
to DEAD and run list_del_rcu(&ifp->if_list).

addrconf_dad_failure() then overwrites DEAD with ERRDAD at errdad:
and schedules a new dad_work.  The work calls ipv6_del_addr()
again, hitting the already-poisoned list entry:

  general protection fault: 0000 [#1] SMP NOPTI
  CPU: 4 PID: 217 Comm: kworker/4:1
  Workqueue: ipv6_addrconf addrconf_dad_work
  RIP: 0010:ipv6_del_addr+0xe9/0x280
  RAX: dead000000000122
  Call Trace:
   addrconf_dad_stop+0x113/0x140
   addrconf_dad_work+0x28c/0x430
   process_one_work+0x1eb/0x3b0
   worker_thread+0x4d/0x400
   kthread+0x104/0x140
   ret_from_fork+0x35/0x40

Fold the addrconf_dad_end() logic into addrconf_dad_failure() under
a single ifp->lock critical section.  The STABLE_PRIVACY branch
temporarily drops ifp->lock around address regeneration, so at
lock_errdad: verify the state is still POSTDAD before transitioning
to ERRDAD; bail out otherwise to avoid overwriting a state set by
another path while the lock was released.

## Affected

- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 47b05836705b63dab93d9ac7c69a3a507375ef80`
- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < d21be7d051012c6b572fa4e3334443c250216f7b`
- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 875c284c0f98b042bb97abad460f63a24c977f88`
- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 8ed0ce9ea58d677d1bac92614ee5f60f8ea57363`
- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb`
- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < b61af0268e3d1308c466bf0be5dced844eafc1ef`
- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < e889aa99ad3ed48bb0ddcff6475b17542532d18b`
- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 627ac78f2741e2ebd2225e2e953b6964a8a9182f`
- `Linux 835b474b8f70fa68d68abffad37378e92f661802`
- `Linux >= 3.10.105 < 3.11`
- `Linux 3.14`

## Remediation

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