CVE-2025-40006

Local memory corruption via hugetlbfs folio race

Published Oct 20, 2025 · Updated Oct 20, 2025

A race condition in affected Linux kernel releases allows local users to corrupt memory via concurrent hugetlbfs hole punching and page migration. remove_inode_single_folio checks folio_mapped() without holding the folio lock, mistakes a migration entry for an unmapped folio, and deletes it before migration restores the mapping. An ordinary local user can control both racing threads; the resulting stale writable mapping permits access to recycled huge-page memory and can panic the kernel.

CVSS severity7.8
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in affected Linux kernel releases allows local users to corrupt memory via concurrent hugetlbfs hole punching and page migration. remove_inode_single_folio checks folio_mapped() without holding the folio lock, mistakes a migration entry for an unmapped folio, and deletes it before migration restores the mapping. An ordinary local user can control both racing threads; the resulting stale writable mapping permits access to recycled huge-page memory and can panic the kernel.

The record

CVE
CVE-2025-40006
Published
Oct 20, 2025
Updated
Oct 20, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 20, 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=4.5
  2. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <21ee79ce938127f88fe07e409c1817f477dbe7ea
  3. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <3e851448078f5b01f6264915df3cfef75e323a12
  4. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <7b7387650dcf2881fd8bb55bcf3c8bd6c9542dd7
  5. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <910d7749346c4b0acdc6e4adfdc4a9984281a206
  6. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <91f548e920fbf8be3f285bfa3fa045ae017e836d
  7. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <bc1c9ce8aeff45318332035dbef9713fb9e982d7
  8. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <c1dc0524ab2cc3982d4e0d2bfac71a0cd4d65c39
  9. Affected versionversion=4aae8d1c051ea00b456da6811bc36d1f69de5445 <c9c2a51f91aea70e89b496cac360cd795a2b3c26

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.5; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <21ee79ce938127f88fe07e409c1817f477dbe7ea; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <3e851448078f5b01f6264915df3cfef75e323a12; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <7b7387650dcf2881fd8bb55bcf3c8bd6c9542dd7; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <910d7749346c4b0acdc6e4adfdc4a9984281a206; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <91f548e920fbf8be3f285bfa3fa045ae017e836d; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <bc1c9ce8aeff45318332035dbef9713fb9e982d7; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <c1dc0524ab2cc3982d4e0d2bfac71a0cd4d65c39; version=4aae8d1c051ea00b456da6811bc36d1f69de5445 <c9c2a51f91aea70e89b496cac360cd795a2b3c26

Published CVSS scores

5.7UbuntuCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.8LinuxCVSS: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

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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