---
id: CVE-2026-74597
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ip6_tunnel: clear skb2->cb[] in ip6ip6_err()

  ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the
  quoted inner IPv6 packet, and then passes the clone to i…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ip6_tunnel: clear skb2->cb[] in ip6ip6_err()

  ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the
  quoted inner IPv6 packet, and then passes the clone to i…
severity: none
published: '2026-08-22'
updated: '2026-08-22'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74597'
references:
  - url: 'https://git.kernel.org/stable/c/0dadb0620ab65949a8bc2439dd28ea3c942fe87d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/44fe898df302e91c5ee5acbc71ffa74e78e6c183'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/484134e1eb07d700a73b1e4bbf3fb503e299be60'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4eb15c465337b18f44716c499cd6ad63eee0ad54'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/64e41736a26f37ab6215bc2e6df125df05aceb08'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b6816536a2990c0db44a26130a03e40b441e829b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f803c086399da277b5d0ff36a107d0f162751800'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fbf40faa0414b753212494ad197542002e66ed9e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
ingestedAt: '2026-08-23T09:45:33.621Z'
epss: 0.00755
epssPercentile: 0.53119
---

## Overview

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

ip6_tunnel: clear skb2->cb[] in ip6ip6_err()

ip6ip6_err() clones an outer IPv6 ICMP error skb, pulls it to the
quoted inner IPv6 packet, and then passes the clone to icmpv6_send().
The clone still carries the outer packet's inet6_skb_parm in skb->cb.

If the outer packet had a Home Address Option, IP6CB(skb2)->dsthao
remains non-zero after skb_pull(). icmpv6_send() later calls
mip6_addr_swap(), which uses that stale dsthao offset against the quoted
inner packet. A malformed inner destination-options header can then make
the HAO lookup and address swap run past the end of the quoted packet
and corrupt skb_shared_info.

Clear skb2->cb[] before pulling the quoted inner IPv6 packet so the
reply path does not reuse metadata left by the outer IPv6 stack.

## Remediation

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