---
id: CVE-2026-74630
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: prevent in6_dev_get() from resurrecting inet6_dev

  in6_dev_get() reads dev->ip6_ptr under RCU and then unconditionally
  increments its refcount
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: prevent in6_dev_get() from resurrecting inet6_dev

  in6_dev_get() reads dev->ip6_ptr under RCU and then unconditionally
  increments its refcount. Device teardown ca…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
published: '2026-08-22'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74630'
references:
  - url: 'https://git.kernel.org/stable/c/0e243671bc7b8eaf00f83dd2f4367436dc0cff98'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/145812b678de9f3b59780173be3c0d22ed60dd93'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/14e812ab41df0cac033479da835ec9a5de633404'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1c206d461c680c3151daa3c89fc26eaf5bf98a7f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/680fbd7942185448eadb990a3d10a53eb946b702'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/785d908f8d21c8bc78b6fb2c2932ab662bf6918a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/aedcfefdb5b7ed7f8a6196a3e68a25bdbe51d2f8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cc5bd568f9b7683e60841b6fd02c10d64535bd6e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00128
epssPercentile: 0.02167
ingestedAt: '2026-10-14T13:30:58.521Z'
---

## Overview

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

ipv6: prevent in6_dev_get() from resurrecting inet6_dev

in6_dev_get() reads dev->ip6_ptr under RCU and then unconditionally
increments its refcount. Device teardown can clear the pointer and drop
the last reference between these operations. The increment then
resurrects an object whose RCU free has already been queued, so callers
can use it after it is freed.

Use refcount_inc_not_zero() and return NULL when the object has already
reached zero. RCU keeps the memory accessible through the attempted
reference acquisition, and a successful increment pins the object for
the caller.

An independent run on the exact unpatched 6f5156d7a31a (v7.2-rc3)
kernel reproduced the invalid reference acquisition as UID 1000:

  refcount_t: addition on 0; use-after-free.
  ip6_mc_source+0xef4/0x17e0

It was followed by the corresponding reference underflow in
ip6_mc_source(). The supplied trace from the same unpatched revision
additionally shows the access after the RCU read-side section ends:

  BUG: KASAN: slab-use-after-free in mutex_lock+0x76/0xe0
  Write of size 8 at addr ffff888015b50240 by task poc/1219

Bug found and triaged by OpenAI Security Research and
validated by Trail of Bits.

## Remediation

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