---
id: CVE-2026-53228
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: sit: reload inner IPv6 header after GSO offloads

  ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function
  entry and continues using it after iptunnel…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ipv6: sit: reload inner IPv6 header after GSO offloads

  ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function
  entry and continues using it after iptunnel…
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'
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 3.18, < 5.10.259'
  - 'linux_kernel >= 5.11, < 5.15.210'
  - 'linux_kernel >= 5.16, < 6.1.176'
  - 'linux_kernel >= 6.2, < 6.6.143'
  - 'linux_kernel >= 6.7, < 6.12.94'
  - 'linux_kernel >= 6.13, < 6.18.36'
  - 'linux_kernel >= 6.19, < 7.0.13'
  - linux_kernel = 7.1
patched:
  - linux_kernel 7.0.13
published: '2026-06-25'
updated: '2026-07-02'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53228'
references:
  - url: 'https://git.kernel.org/stable/c/0bfa7bba1f41aaf5f0604dc712bb4701493e3aa0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1132e5edc2866c3530be17622153a597095f0e43'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2fa49b2715e1bad12ce3b0fa64e234d9582c8193'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/59f80c919713250fe5d25a4d9aea4e49580fa1d4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9c67b44edb3598d234efae6e44649eb993c03da5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cb658c2f5f7977c2a1c77c9f239f4bc8196edb5c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f0e42f0c4337b1f220de1ddd63f47197c7dee4de'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fddd41445a0537b093e6b3f6232c9933cad1e48b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53228.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-53228'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492733'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-53228'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53228'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026062507-CVE-2026-53228-f3f1@gregkh/T
  - url: 'https://access.redhat.com/errata/RHSA-2026:64775'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68531'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68532'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00755
epssPercentile: 0.53116
ingestedAt: '2026-07-03T13:02:28.072Z'
cwe:
  - CWE-825
scores:
  nvd: 9.8
  vendor: 7
---

## Overview

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

ipv6: sit: reload inner IPv6 header after GSO offloads

ipip6_tunnel_xmit() caches the inner IPv6 header pointer at function
entry and continues using it after iptunnel_handle_offloads().

For GSO skbs, iptunnel_handle_offloads() calls skb_header_unclone().
When the skb header is cloned, skb_header_unclone() can call
pskb_expand_head(), which may move the skb head. The pskb_expand_head()
contract requires pointers into the skb header to be reloaded after the
call.

If the later skb_realloc_headroom() branch is not taken, SIT uses the
stale iph6 pointer to read the inner hop limit and DS field. That can
read from a freed skb head after the old head's remaining clone is
released.

Reload iph6 after the offload helper succeeds and before subsequent
reads from the inner IPv6 header. Keep the existing reload after
skb_realloc_headroom(), since that branch can also replace the skb.

## Affected

- `linux_kernel >= 3.18, < 5.10.259`
- `linux_kernel >= 5.11, < 5.15.210`
- `linux_kernel >= 5.16, < 6.1.176`
- `linux_kernel >= 6.2, < 6.6.143`
- `linux_kernel >= 6.7, < 6.12.94`
- `linux_kernel >= 6.13, < 6.18.36`
- `linux_kernel >= 6.19, < 7.0.13`
- `linux_kernel = 7.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.13`

## Vendor advisories

- **RHSA-2026:64775** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-09-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:64775)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 9 · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53228.json)
- **RHSA-2026:68531** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68531)
- **RHSA-2026:68532** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68532)