CVE-2023-53516

Kernel heap over-read via unvalidated netlink attribute

Published Oct 1, 2025 · Updated Oct 1, 2025

Out-of-bounds read in Linux 6.4 through 6.4.7 allows local users to access kernel heap data via a malformed macvlan netlink attribute. The macvlan_policy table omits an NLA_S32 policy for IFLA_MACVLAN_BC_CUTOFF, so the parser accepts a zero-byte value instead of requiring four bytes. Low-privileged local access is required; the published description establishes an out-of-bounds read but does not document code execution, privilege escalation, or a reliable crash.

CVSS severity7.8
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 Linux 6.4 through 6.4.7 allows local users to access kernel heap data via a malformed macvlan netlink attribute. The macvlan_policy table omits an NLA_S32 policy for IFLA_MACVLAN_BC_CUTOFF, so the parser accepts a zero-byte value instead of requiring four bytes. Low-privileged local access is required; the published description establishes an out-of-bounds read but does not document code execution, privilege escalation, or a reliable crash.

The record

CVE
CVE-2023-53516
Published
Oct 1, 2025
Updated
Oct 1, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=6.4
  2. Affected versionversion=954d1fa1ac93aa8a66f7d9a9ba545cf7f020d348 <55cef78c244d0d076f5a75a35530ca63c92f4426
  3. Affected versionversion=954d1fa1ac93aa8a66f7d9a9ba545cf7f020d348 <79f44709aa7a744fbfbadd4aef678443290c6991

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.4; version=954d1fa1ac93aa8a66f7d9a9ba545cf7f020d348 <55cef78c244d0d076f5a75a35530ca63c92f4426; version=954d1fa1ac93aa8a66f7d9a9ba545cf7f020d348 <79f44709aa7a744fbfbadd4aef678443290c6991

Published CVSS scores

5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
7.8CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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

No sourced classifications are available.

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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