---
id: CVE-2026-80792
title: 'ipv6: fix use-after-free in ip6_finish_output2()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: fix use-after-free in ip6_finish_output2()

  ip6_finish_output2() caches a pointer to the IPv6 destination
  address (daddr) before invoking lwtunnel_xmit().  The LW…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 4132c4ad00ddbf3a175ea0d2c775b662a32f4c85 <
    75e0a544ebe9af663ef53ca21e9e9185c51fb54a
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    c95f01b78266828a57060d754fcbfc92123a98ed
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    d960881b9312e781a3429aabceb223ce6b7c882f
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    087ee0d914aaae929f1660c9ca878e367655ba1a
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    3c770ac4e6f07af7c7b40c474a3efc61ffed7862
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    3dc98e5fe82d069dd29b124ffbdb679331dfea43
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    99219c82804f266189388e8bf1cf5135d10d5515
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    73a187384a8c8b983c7fea046d716b6752a1e7a3
  - >-
    Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 <
    d0d48d999b0eee6bb176ef4e39d9be868fa80f7e
  - Linux 1598154fd28ffa4a55beae1970475fd6776554b6
  - Linux >= 5.10.233 < 5.10.267
  - Linux >= 5.4.289 < 5.5
  - Linux 5.15
published: '2026-09-04'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:43:45.535Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80792'
references:
  - url: 'https://git.kernel.org/stable/c/75e0a544ebe9af663ef53ca21e9e9185c51fb54a'
  - url: 'https://git.kernel.org/stable/c/c95f01b78266828a57060d754fcbfc92123a98ed'
  - url: 'https://git.kernel.org/stable/c/d960881b9312e781a3429aabceb223ce6b7c882f'
  - url: 'https://git.kernel.org/stable/c/087ee0d914aaae929f1660c9ca878e367655ba1a'
  - url: 'https://git.kernel.org/stable/c/3c770ac4e6f07af7c7b40c474a3efc61ffed7862'
  - url: 'https://git.kernel.org/stable/c/3dc98e5fe82d069dd29b124ffbdb679331dfea43'
  - url: 'https://git.kernel.org/stable/c/99219c82804f266189388e8bf1cf5135d10d5515'
  - url: 'https://git.kernel.org/stable/c/73a187384a8c8b983c7fea046d716b6752a1e7a3'
  - url: 'https://git.kernel.org/stable/c/d0d48d999b0eee6bb176ef4e39d9be868fa80f7e'
tags:
  - cve.org
epss: 0.00195
epssPercentile: 0.08585
ingestedAt: '2026-10-19T09:16:01.530Z'
---

## Overview

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

ipv6: fix use-after-free in ip6_finish_output2()

ip6_finish_output2() caches a pointer to the IPv6 destination
address (daddr) before invoking lwtunnel_xmit().  The LWT-BPF
transmit path or other encapsulation operations within
lwtunnel_xmit() can reallocate the skb head, freeing the memory
that daddr points to.  When lwtunnel_xmit() returns
LWTUNNEL_XMIT_CONTINUE, the function continues to use the stale
daddr pointer to compute the nexthop and to look up or create the
neighbour entry.  This results in a use-after-free read, which can
leak sensitive kernel data, pollute the neighbour table with
arbitrary values, misdirect traffic, or crash the system.

Fix this by re-fetching the IPv6 header and the destination
address pointer after lwtunnel_xmit() returns
LWTUNNEL_XMIT_CONTINUE, ensuring that the subsequent nexthop
computation and neighbour lookup operate on valid memory.

## Affected

- `Linux >= 4132c4ad00ddbf3a175ea0d2c775b662a32f4c85 < 75e0a544ebe9af663ef53ca21e9e9185c51fb54a`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < c95f01b78266828a57060d754fcbfc92123a98ed`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < d960881b9312e781a3429aabceb223ce6b7c882f`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < 087ee0d914aaae929f1660c9ca878e367655ba1a`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < 3c770ac4e6f07af7c7b40c474a3efc61ffed7862`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < 3dc98e5fe82d069dd29b124ffbdb679331dfea43`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < 99219c82804f266189388e8bf1cf5135d10d5515`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < 73a187384a8c8b983c7fea046d716b6752a1e7a3`
- `Linux >= e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 < d0d48d999b0eee6bb176ef4e39d9be868fa80f7e`
- `Linux 1598154fd28ffa4a55beae1970475fd6776554b6`
- `Linux >= 5.10.233 < 5.10.267`
- `Linux >= 5.4.289 < 5.5`
- `Linux 5.15`

## Remediation

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