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VulnerabilityPublished Updated

CVE-2025-40006: Linux kernel · mm/hugetlb: fix folio is still mapped when deleted

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1100.107~20.04.2 : patch Linux kernel soon.

Data as of 28 Oct 2026, 11:19 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.15.0-1100.107~20.04.2, 5.15.0-1110.119~20.04.1, 5.15.0-1100.109~20.04.1 +68
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Oct 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threatsAffected
  • <6.17.0-6.6
Fixed in
  • 6.17.0-6.6
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1003.3
Fixed in
  • 6.17.0-1003.3
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1006.6
Fixed in
  • 6.17.0-1006.6
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1003.3
Fixed in
  • 6.17.0-1003.3
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1003.3
Fixed in
  • 6.17.0-1003.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been released in multiple fixed Linux kernel versions as listed. Users should update to one of the fixed kernel versions to remediate this vulnerability. After applying the update, a system reboot is required to ensure the fix is active. No additional mitigations are necessary beyond applying the official kernel updates.

Description

CVE-2025-40006 is a vulnerability in the Linux kernel's huge page memory management subsystem where a fix folio remains mapped after deletion due to a race condition during migration and fallocation. This can trigger a kernel BUG related to page cache accounting. The issue arises because remove_inode_single_folio may fail to unmap a folio if it is migrated and the folio lock is not held, causing inconsistent page state and system instability. This flaw affects certain Linux kernel versions and has been addressed in updated kernel releases.

References

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