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Response snapshot Oct 28, 2026, 20:06 UTC

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VulnerabilityCVE-2023-53726

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

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.

At a glance

Exploited
Not known
Severity
7.1 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2023-53726 (opens a new tab)

What happened

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.

Continue reading

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

Scores and how they were measured

CVSS base severity

7.1

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2023-53726 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 28). Linux kernel: arm64: csum: Fix OoB access in IP checksum code for negative lengths (CVE-2023-53726). https://kevwire.com/record/CVE-2023-53726

MLA

"Linux kernel: arm64: csum: Fix OoB access in IP checksum code for negative lengths (CVE-2023-53726)." KEVWire, 28 Oct. 2026, kevwire.com/record/CVE-2023-53726.

Chicago

KEVWire. "Linux kernel: arm64: csum: Fix OoB access in IP checksum code for negative lengths (CVE-2023-53726)." Last modified October 28, 2026. https://kevwire.com/record/CVE-2023-53726.

Evidence summary (plain text)

Linux kernel: arm64: csum: Fix OoB access in IP checksum code for negative lengths (Oct 22, 2025).
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…
CVSS 7.1 (version 3.1; evidence as of Oct 28, 2026; https://nvd.nist.gov/vuln/detail/CVE-2023-53726).
Sources:
NVD CVE-2023-53726: https://nvd.nist.gov/vuln/detail/CVE-2023-53726
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T18:31:08.168Z&lastModEndDate=2026-10-28T20:05:58.019Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T17:55:58.678Z&lastModEndDate=2026-10-28T19:30:56.852Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2023-53726.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 28, 2026, 20:05 UTC. Ingestion is not an independent editorial investigation.

NVD status: Deferred. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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