CVE-2023-52993

Crash-kernel boot failure via legacy timer resend

Published Mar 27, 2025 · Updated May 11, 2026

NULL pointer dereference in affected Linux kernel releases allows local users to prevent a crash kernel from booting after a system crash. The x86 i8259 setup omits IRQ_LEVEL for level-triggered legacy PIC interrupts, so a spurious APIC IRQ0 is resent in tasklet context where get_irq_regs() returns NULL. Reachability requires local privileges, a system crash, legacy PIC timer handling, and the spurious interrupt; the bounded consequence is crash-kernel boot failure.

CVSS severity5.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

NULL pointer dereference in affected Linux kernel releases allows local users to prevent a crash kernel from booting after a system crash. The x86 i8259 setup omits IRQ_LEVEL for level-triggered legacy PIC interrupts, so a spurious APIC IRQ0 is resent in tasklet context where get_irq_regs() returns NULL. Reachability requires local privileges, a system crash, legacy PIC timer handling, and the spurious interrupt; the bounded consequence is crash-kernel boot failure.

The record

CVE
CVE-2023-52993
Published
Mar 27, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record 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=2.6.18
  2. Affected versionversion=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <0b08201158f177aab469e356b4d6af24fdd118df
  3. Affected versionversion=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <137f1b47da5f58805da42c1b7811e28c1e353f39
  4. Affected versionversion=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <496975d1a2937f4baadf3d985991b13fc4fc4f27
  5. Affected versionversion=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <5fa55950729d0762a787451dc52862c3f850f859
  6. Affected versionversion=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <744fe9be9665227335539b7a77ece8d9ff62b6c0
  7. Affected versionversion=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <8770cd9d7c14aa99c255a0d08186f0be953e1638
  8. Affected versionversion=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <e284c273dbb4c1ed68d4204bff94d0b10e4a90f5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.18; version=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <0b08201158f177aab469e356b4d6af24fdd118df; version=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <137f1b47da5f58805da42c1b7811e28c1e353f39; version=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <496975d1a2937f4baadf3d985991b13fc4fc4f27; version=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <5fa55950729d0762a787451dc52862c3f850f859; version=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <744fe9be9665227335539b7a77ece8d9ff62b6c0; version=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <8770cd9d7c14aa99c255a0d08186f0be953e1638; version=a4633adcdbc15ac51afcd0e1395de58cee27cf92 <e284c273dbb4c1ed68d4204bff94d0b10e4a90f5

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5CISA-ADPCVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
T1499.004Application or System Exploitation

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo