CVE-2025-40244

Kernel memory compromise via uninitialized HFS+ lookup state

Published Dec 4, 2025 · Updated Aug 5, 2026

Improper initialization in the Linux kernel HFS+ driver allows local users to crash the host through a crafted HFS+ volume. A failed extent-tree lookup leaves hfs_find_data fields uninitialized, and later HFS+ code consumes them as record offsets and lengths, enabling out-of-bounds kernel reads and writes. Reachability requires a locally mounted attacker-authored HFS+ device or image followed by ordinary file operations; the demonstrated outcome is a kernel panic.

CVSS severity7.0
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper initialization in the Linux kernel HFS+ driver allows local users to crash the host through a crafted HFS+ volume. A failed extent-tree lookup leaves hfs_find_data fields uninitialized, and later HFS+ code consumes them as record offsets and lengths, enabling out-of-bounds kernel reads and writes. Reachability requires a locally mounted attacker-authored HFS+ device or image followed by ordinary file operations; the demonstrated outcome is a kernel panic.

The record

CVE
CVE-2025-40244
Published
Dec 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <14c673a2f3ecf650b694a52a88688f1d71849899
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4840ceadef4290c56cc422f0fc697655f3cbf070
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <99202d94909d323a30d154ab0261c0a07166daec
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a5bfb13b4f406aef1a450f99d22d3e48df01528c
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b8a72692aa42b7dcd179a96b90bc2763ac74576a
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c135b8dca65526aa5b8814e9954e0ae317d9c598
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c1ec90bed504640a42bb20a5f413be39cd17ad71
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d7e313039a8f3a6ee072dc5ff4643234d2d735cf
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <14c673a2f3ecf650b694a52a88688f1d71849899; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4840ceadef4290c56cc422f0fc697655f3cbf070; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <99202d94909d323a30d154ab0261c0a07166daec; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a5bfb13b4f406aef1a450f99d22d3e48df01528c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b8a72692aa42b7dcd179a96b90bc2763ac74576a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c135b8dca65526aa5b8814e9954e0ae317d9c598; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c1ec90bed504640a42bb20a5f413be39cd17ad71; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d7e313039a8f3a6ee072dc5ff4643234d2d735cf; version=2.6.12

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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