CVE-2025-40243

Volume corruption via uninitialized HFS bitmap

Published Dec 4, 2025 · Updated Aug 5, 2026

Uninitialized memory use in the Linux kernel HFS driver allows local users to corrupt volumes through file extension operations. hfs_mdb_get allocates the 8 KiB allocation bitmap with kmalloc, and a short disk read leaves stale slab bytes that hfs_find_set_zero_bits treats as allocation state. Reaching the flaw requires a mounted HFS image or device; subsequent truncate or write operations can corrupt filesystem metadata and interrupt the host.

CVSS severityUnavailable
Unscored
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

Uninitialized memory use in the Linux kernel HFS driver allows local users to corrupt volumes through file extension operations. hfs_mdb_get allocates the 8 KiB allocation bitmap with kmalloc, and a short disk read leaves stale slab bytes that hfs_find_set_zero_bits treats as allocation state. Reaching the flaw requires a mounted HFS image or device; subsequent truncate or write operations can corrupt filesystem metadata and interrupt the host.

The record

CVE
CVE-2025-40243
Published
Dec 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
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 <2048ec5b98dbdfe0b929d2e42dc7a54c389c53dd
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2a112cdd66f5a132da5235ca31a320528c86bf33
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3b447fd401824e1ccf0b769188edefe866a1e676
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <502fa92a71f344611101bd04ef1a595b8b6014f5
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bf1683078fbdd09a7f7f9b74121ebaa03432bd00
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cfafefcb0e1fc60135f7040f4aed0a4aef4f76ca
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e148ed5cda8fd96d4620c4622fb02f552a2d166a
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fc56548fca732f3d3692c83b40db796259a03887
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2048ec5b98dbdfe0b929d2e42dc7a54c389c53dd; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2a112cdd66f5a132da5235ca31a320528c86bf33; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3b447fd401824e1ccf0b769188edefe866a1e676; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <502fa92a71f344611101bd04ef1a595b8b6014f5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bf1683078fbdd09a7f7f9b74121ebaa03432bd00; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <cfafefcb0e1fc60135f7040f4aed0a4aef4f76ca; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e148ed5cda8fd96d4620c4622fb02f552a2d166a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fc56548fca732f3d3692c83b40db796259a03887; version=2.6.12

Published CVSS scores

No CVSS assessment is available in this record.

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

No sourced classifications are available.

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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