CVE-2023-53726

Kernel-memory disclosure or crash via negative checksum length

Published Oct 22, 2025 · Updated Oct 22, 2025

Out-of-bounds read in arm64 checksum code in affected Linux 5.6 through 6.5 releases allows local users to disclose kernel memory or crash the host. The do_csum function accepts an attacker-controlled negative length, performs an undefined shift, and walks beyond the intended buffer while calculating a packet checksum. A local process with AF_PACKET access can trigger the TX GSO path without user interaction; the resulting checksum exposes a function of kernel memory, while sufficiently large reads can panic or oops the host.

CVSS severity7.1
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in arm64 checksum code in affected Linux 5.6 through 6.5 releases allows local users to disclose kernel memory or crash the host. The do_csum function accepts an attacker-controlled negative length, performs an undefined shift, and walks beyond the intended buffer while calculating a packet checksum. A local process with AF_PACKET access can trigger the TX GSO path without user interaction; the resulting checksum exposes a function of kernel memory, while sufficiently large reads can panic or oops the host.

The record

CVE
CVE-2023-53726
Published
Oct 22, 2025
Updated
Oct 22, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 22, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.6
  2. Affected versionversion=5777eaed566a1d63e344d3dd8f2b5e33be20643e <5a85727239a23de1cc8d93985f1056308128f3e2
  3. Affected versionversion=5777eaed566a1d63e344d3dd8f2b5e33be20643e <8bd795fedb8450ecbef18eeadbd23ed8fc7630f5
  4. Affected versionversion=5777eaed566a1d63e344d3dd8f2b5e33be20643e <9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523
  5. Affected versionversion=5777eaed566a1d63e344d3dd8f2b5e33be20643e <a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f
  6. Affected versionversion=5777eaed566a1d63e344d3dd8f2b5e33be20643e <ba0b46166b8e547024d02345a68b747841931ad2
  7. Affected versionversion=5777eaed566a1d63e344d3dd8f2b5e33be20643e <fcdf904e866de0e3715835e50409fda3b2590527

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.6; version=5777eaed566a1d63e344d3dd8f2b5e33be20643e <5a85727239a23de1cc8d93985f1056308128f3e2; version=5777eaed566a1d63e344d3dd8f2b5e33be20643e <8bd795fedb8450ecbef18eeadbd23ed8fc7630f5; version=5777eaed566a1d63e344d3dd8f2b5e33be20643e <9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523; version=5777eaed566a1d63e344d3dd8f2b5e33be20643e <a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f; version=5777eaed566a1d63e344d3dd8f2b5e33be20643e <ba0b46166b8e547024d02345a68b747841931ad2; version=5777eaed566a1d63e344d3dd8f2b5e33be20643e <fcdf904e866de0e3715835e50409fda3b2590527

Published CVSS scores

7.1Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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