---
id: CVE-2023-53726
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  arm64: csum: Fix OoB access in IP checksum code for negative lengths

  Although commit c2c24edb1d9c ("arm64: csum: Fix pathological zero-length
  calls") added an early re…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  arm64: csum: Fix OoB access in IP checksum code for negative lengths

  Although commit c2c24edb1d9c ("arm64: csum: Fix pathological zero-length
  calls") added an early re…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5777eaed566a1d63e344d3dd8f2b5e33be20643e <
    5a85727239a23de1cc8d93985f1056308128f3e2
  - >-
    Linux >= 5777eaed566a1d63e344d3dd8f2b5e33be20643e <
    9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523
  - >-
    Linux >= 5777eaed566a1d63e344d3dd8f2b5e33be20643e <
    ba0b46166b8e547024d02345a68b747841931ad2
  - >-
    Linux >= 5777eaed566a1d63e344d3dd8f2b5e33be20643e <
    a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f
  - >-
    Linux >= 5777eaed566a1d63e344d3dd8f2b5e33be20643e <
    fcdf904e866de0e3715835e50409fda3b2590527
  - >-
    Linux >= 5777eaed566a1d63e344d3dd8f2b5e33be20643e <
    8bd795fedb8450ecbef18eeadbd23ed8fc7630f5
  - Linux 5.6
published: '2025-10-22'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:17:47.430'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2023-53726'
references:
  - url: 'https://git.kernel.org/stable/c/5a85727239a23de1cc8d93985f1056308128f3e2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8bd795fedb8450ecbef18eeadbd23ed8fc7630f5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ba0b46166b8e547024d02345a68b747841931ad2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fcdf904e866de0e3715835e50409fda3b2590527'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.0015
epssPercentile: 0.04141
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-15T21:36:49.302091Z'
ingestedAt: '2026-10-15T22:48:25.418Z'
---

## Overview

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

arm64: csum: Fix OoB access in IP checksum code for negative lengths

Although commit c2c24edb1d9c ("arm64: csum: Fix pathological zero-length
calls") added an early return for zero-length input, syzkaller has
popped up with an example of a _negative_ length which causes an
undefined shift and an out-of-bounds read:

 | BUG: KASAN: slab-out-of-bounds in do_csum+0x44/0x254 arch/arm64/lib/csum.c:39
 | Read of size 4294966928 at addr ffff0000d7ac0170 by task syz-executor412/5975
 |
 | CPU: 0 PID: 5975 Comm: syz-executor412 Not tainted 6.4.0-rc4-syzkaller-g908f31f2a05b #0
 | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
 | Call trace:
 |  dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233
 |  show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240
 |  __dump_stack lib/dump_stack.c:88 [inline]
 |  dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 |  print_address_description mm/kasan/report.c:351 [inline]
 |  print_report+0x174/0x514 mm/kasan/report.c:462
 |  kasan_report+0xd4/0x130 mm/kasan/report.c:572
 |  kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:187
 |  __kasan_check_read+0x20/0x30 mm/kasan/shadow.c:31
 |  do_csum+0x44/0x254 arch/arm64/lib/csum.c:39
 |  csum_partial+0x30/0x58 lib/checksum.c:128
 |  gso_make_checksum include/linux/skbuff.h:4928 [inline]
 |  __udp_gso_segment+0xaf4/0x1bc4 net/ipv4/udp_offload.c:332
 |  udp6_ufo_fragment+0x540/0xca0 net/ipv6/udp_offload.c:47
 |  ipv6_gso_segment+0x5cc/0x1760 net/ipv6/ip6_offload.c:119
 |  skb_mac_gso_segment+0x2b4/0x5b0 net/core/gro.c:141
 |  __skb_gso_segment+0x250/0x3d0 net/core/dev.c:3401
 |  skb_gso_segment include/linux/netdevice.h:4859 [inline]
 |  validate_xmit_skb+0x364/0xdbc net/core/dev.c:3659
 |  validate_xmit_skb_list+0x94/0x130 net/core/dev.c:3709
 |  sch_direct_xmit+0xe8/0x548 net/sched/sch_generic.c:327
 |  __dev_xmit_skb net/core/dev.c:3805 [inline]
 |  __dev_queue_xmit+0x147c/0x3318 net/core/dev.c:4210
 |  dev_queue_xmit include/linux/netdevice.h:3085 [inline]
 |  packet_xmit+0x6c/0x318 net/packet/af_packet.c:276
 |  packet_snd net/packet/af_packet.c:3081 [inline]
 |  packet_sendmsg+0x376c/0x4c98 net/packet/af_packet.c:3113
 |  sock_sendmsg_nosec net/socket.c:724 [inline]
 |  sock_sendmsg net/socket.c:747 [inline]
 |  __sys_sendto+0x3b4/0x538 net/socket.c:2144

Extend the early return to reject negative lengths as well, aligning our
implementation with the generic code in lib/checksum.c

## Remediation

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