CVE-2025-40230

Kernel panic via poisoned THP re-read

Published Dec 4, 2025 · Updated May 11, 2026

Denial of service in the Linux kernel memory-failure path allows attackers to panic an x86 server while splitting a poisoned THP. During memory_failure(), try_to_map_unused_to_zeropage() calls memchr_inv() while scanning the huge page and re-reads the already poisoned page, causing a second in-kernel machine check. Reachability requires a hardware-poisoned transparent huge page mapped to userspace; the second machine check crashes the host instead of terminating only the affected process.

CVSS severity7.0
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel memory-failure path allows attackers to panic an x86 server while splitting a poisoned THP. During memory_failure(), try_to_map_unused_to_zeropage() calls memchr_inv() while scanning the huge page and re-reads the already poisoned page, causing a second in-kernel machine check. Reachability requires a hardware-poisoned transparent huge page mapped to userspace; the second machine check crashes the host instead of terminating only the affected process.

The record

CVE
CVE-2025-40230
Published
Dec 4, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 4, 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

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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=6.12
  2. Affected versionversion=b1f202060afeb7fcb98473929d26fd3d2093b067 <6fc0a7c99e973a50018c8b4be34914a1b5c7b383
  3. Affected versionversion=b1f202060afeb7fcb98473929d26fd3d2093b067 <841a8bfcbad94bb1ba60f59ce34f75259074ae0d
  4. Affected versionversion=b1f202060afeb7fcb98473929d26fd3d2093b067 <92acf4b04f255d2f0f6770bb0d0a208d8ffb2b77

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=b1f202060afeb7fcb98473929d26fd3d2093b067 <6fc0a7c99e973a50018c8b4be34914a1b5c7b383; version=b1f202060afeb7fcb98473929d26fd3d2093b067 <841a8bfcbad94bb1ba60f59ce34f75259074ae0d; version=b1f202060afeb7fcb98473929d26fd3d2093b067 <92acf4b04f255d2f0f6770bb0d0a208d8ffb2b77

Published CVSS scores

7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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