---
id: CVE-2026-74398
title: |-
  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…
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'
cwe:
  - CWE-672
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux 8
  - enterprise_linux 9
published: '2026-08-15'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:17:25.390'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74398'
references:
  - url: 'https://git.kernel.org/stable/c/3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/47b05836705b63dab93d9ac7c69a3a507375ef80'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/627ac78f2741e2ebd2225e2e953b6964a8a9182f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/875c284c0f98b042bb97abad460f63a24c977f88'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8ed0ce9ea58d677d1bac92614ee5f60f8ea57363'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b61af0268e3d1308c466bf0be5dced844eafc1ef'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d21be7d051012c6b572fa4e3334443c250216f7b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e889aa99ad3ed48bb0ddcff6475b17542532d18b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74398.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-74398'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2516924'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-74398'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74398'
  - url: 'https://kernelcve.org/list/?q=CVE-2026-74398'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026081508-CVE-2026-74398-b0da@gregkh/T
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00514
epssPercentile: 0.43607
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T18:55:29.102774Z'
scores:
  nvd: 9.8
  vendor: 5.3
  cna: 9.8
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.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74398.json)