---
id: CVE-2026-100070
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfilter: nf_nat_sip: rewind offset when NAT shrinks the packet

  sashiko says:
   If map_addr() changes the packet length, such as when the public NAT IP
   string is shor…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netfilter: nf_nat_sip: rewind offset when NAT shrinks the packet

  sashiko says:
   If map_addr() changes the packet length, such as when the public NAT IP
   string is shor…
severity: medium
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    6828aca3d82717c2fda92af81c0dda642bc2b465
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    2703f5ea8d85bc729f433ac09ee902084c947122
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    0f4d30e2e49f343fc28ba1e259fd22969b940c46
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    810da5a63549531da78348b0a4545042d84e01e2
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    668cc1c30caedc63070b10d17d5514748988a140
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    e70d48fcf8382581162608a4a322919bfd22aef3
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    c408d416618ebb8a95e3097a13f3b793ea9272ee
  - >-
    Linux >= c978cd3a937141deaf7995b849824af6dacdeae7 <
    16aecbe3036f6097c26b51b12e4c1cf207769690
  - Linux 2.6.26
published: '2026-09-25'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T14:10:59.253'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100070'
references:
  - url: 'https://git.kernel.org/stable/c/0f4d30e2e49f343fc28ba1e259fd22969b940c46'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/16aecbe3036f6097c26b51b12e4c1cf207769690'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2703f5ea8d85bc729f433ac09ee902084c947122'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/668cc1c30caedc63070b10d17d5514748988a140'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6828aca3d82717c2fda92af81c0dda642bc2b465'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/810da5a63549531da78348b0a4545042d84e01e2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c408d416618ebb8a95e3097a13f3b793ea9272ee'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e70d48fcf8382581162608a4a322919bfd22aef3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100070.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-100070'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541421'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-100070'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100070'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-100070.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00115
epssPercentile: 0.01511
ingestedAt: '2026-09-25T14:09:46.377Z'
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe:
  - CWE-212
---

## Overview

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

netfilter: nf_nat_sip: rewind offset when NAT shrinks the packet

sashiko says:
 If map_addr() changes the packet length, such as when the public NAT IP
 string is shorter or longer than the internal IP, coff will still point to
 the offset relative to the pre-mangled packet.
 If the packet shrinks, coff could overshoot the correct position,
 potentially causing the next ct_sip_parse_header_uri() call to silently
 skip bytes and miss subsequent Contact headers. Could this lead to a
 failure to NAT those subsequent headers and leak internal network details?

## 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 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100070.json)