CVE-2023-52463

Kernel crash via unchecked efivarfs read-write remount

Published Feb 23, 2024 · Updated May 23, 2026

NULL pointer dereference in Linux efivarfs allows local users to crash the kernel by writing an EFI variable after a read-write remount. The remount path fails to reject read-write flags when firmware lacks SetVariable support, leaving the callback unset before efivarfs_file_write invokes it. Reaching the fault requires local access, permission to remount efivarfs, firmware without runtime SetVariable support, and an EFI variable write; the consequence is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Linux efivarfs allows local users to crash the kernel by writing an EFI variable after a read-write remount. The remount path fails to reject read-write flags when firmware lacks SetVariable support, leaving the callback unset before efivarfs_file_write invokes it. Reaching the fault requires local access, permission to remount efivarfs, firmware without runtime SetVariable support, and an EFI variable write; the consequence is a kernel crash.

The record

CVE
CVE-2023-52463
Published
Feb 23, 2024
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 23, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 2026Record 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=552952e51fad35670459674bcb8a03bd96fe4646
  2. Affected versionversion=5.7.11 <5.8
  3. Affected versionversion=5.8
  4. Affected versionversion=f88814cc2578c121e6edef686365036db72af0ed <0049fe7e4a85849bdd778cdb72e51a791ff3d737
  5. Affected versionversion=f88814cc2578c121e6edef686365036db72af0ed <0e8d2444168dd519fea501599d150e62718ed2fe
  6. Affected versionversion=f88814cc2578c121e6edef686365036db72af0ed <2aa141f8bc580f8f9811dfe4e0e6009812b73826
  7. Affected versionversion=f88814cc2578c121e6edef686365036db72af0ed <94c742324ed7e42c5bd6a9ed22e4ec6d764db4d8
  8. Affected versionversion=f88814cc2578c121e6edef686365036db72af0ed <d4a714873db0866cc471521114eeac4a5072d548
  9. Affected versionversion=f88814cc2578c121e6edef686365036db72af0ed <d4a9aa7db574a0da64307729cc031fb68597aa8b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=552952e51fad35670459674bcb8a03bd96fe4646; version=5.7.11 <5.8; version=5.8; version=f88814cc2578c121e6edef686365036db72af0ed <0049fe7e4a85849bdd778cdb72e51a791ff3d737; version=f88814cc2578c121e6edef686365036db72af0ed <0e8d2444168dd519fea501599d150e62718ed2fe; version=f88814cc2578c121e6edef686365036db72af0ed <2aa141f8bc580f8f9811dfe4e0e6009812b73826; version=f88814cc2578c121e6edef686365036db72af0ed <94c742324ed7e42c5bd6a9ed22e4ec6d764db4d8; version=f88814cc2578c121e6edef686365036db72af0ed <d4a714873db0866cc471521114eeac4a5072d548; version=f88814cc2578c121e6edef686365036db72af0ed <d4a9aa7db574a0da64307729cc031fb68597aa8b

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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