---
id: CVE-2026-98573
title: 'net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()

  skb_maybe_pull_tail() subtracts skb_headlen(skb) from the unsigned max
  argument and passes the resul…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    9c4e432132a97b82edf28fa172c39f743e6bfb26
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    718747afa5463d9cc5fd9a09f03b2a492edd9b78
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    a0ad0473c09d2e947aecac5c82e637ec85924b12
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    b2da5ed3d8c75e1b729a21b6d3beaed415e263f6
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    6c28c31f051dbf49c71ba7ab7bb9bc905fa1d14b
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    d7f474226809471dc7877435e9c492cc914df0bf
  - >-
    Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 <
    3b4e0b0c008a8c1b474730248cd5b873026c74bd
  - Linux 3.13
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:18:38.914Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98573'
references:
  - url: 'https://git.kernel.org/stable/c/9c4e432132a97b82edf28fa172c39f743e6bfb26'
  - url: 'https://git.kernel.org/stable/c/718747afa5463d9cc5fd9a09f03b2a492edd9b78'
  - url: 'https://git.kernel.org/stable/c/a0ad0473c09d2e947aecac5c82e637ec85924b12'
  - url: 'https://git.kernel.org/stable/c/b2da5ed3d8c75e1b729a21b6d3beaed415e263f6'
  - url: 'https://git.kernel.org/stable/c/6c28c31f051dbf49c71ba7ab7bb9bc905fa1d14b'
  - url: 'https://git.kernel.org/stable/c/cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962'
  - url: 'https://git.kernel.org/stable/c/d7f474226809471dc7877435e9c492cc914df0bf'
  - url: 'https://git.kernel.org/stable/c/3b4e0b0c008a8c1b474730248cd5b873026c74bd'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.257Z'
---

## Overview

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

net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()

skb_maybe_pull_tail() subtracts skb_headlen(skb) from the unsigned max
argument and passes the result to __pskb_pull_tail() as a signed int.  The
function does not ensure that max is at least skb_headlen(skb).

This can happen while parsing IPv6 extension headers when an skb already
has a linear area larger than MAX_IPV6_HDR_LEN.  Once the parser needs data
beyond the linear area, max - skb_headlen(skb) wraps and is converted to a
negative delta.  __pskb_pull_tail() then passes that negative length to
skb_copy_bits(), where it can become a very large copy length.

Pass the requested length itself as the pull bound at the three
extension-header call sites, so the delta can no longer go negative.

## Affected

- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < 9c4e432132a97b82edf28fa172c39f743e6bfb26`
- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < 718747afa5463d9cc5fd9a09f03b2a492edd9b78`
- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < a0ad0473c09d2e947aecac5c82e637ec85924b12`
- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < b2da5ed3d8c75e1b729a21b6d3beaed415e263f6`
- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < 6c28c31f051dbf49c71ba7ab7bb9bc905fa1d14b`
- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962`
- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < d7f474226809471dc7877435e9c492cc914df0bf`
- `Linux >= 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3 < 3b4e0b0c008a8c1b474730248cd5b873026c74bd`
- `Linux 3.13`

## Remediation

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