CVE-2025-40088

Kernel heap disclosure via unchecked HFS+ length

Published Oct 30, 2025 · Updated Aug 5, 2026

Out-of-bounds read in Linux HFS+ support allows local users to disclose kernel heap data through a crafted catalog key. hfsplus_strcasecmp uses the attacker-controlled HFS+ Unicode length field directly as its comparison-loop bound, reading beyond the catalog-key allocation. An unprivileged local user who can traverse a mounted malicious HFS+ volume can expose adjacent kernel heap data or trigger a kernel oops and filesystem failure.

CVSS severity7.1
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Linux HFS+ support allows local users to disclose kernel heap data through a crafted catalog key. hfsplus_strcasecmp uses the attacker-controlled HFS+ Unicode length field directly as its comparison-loop bound, reading beyond the catalog-key allocation. An unprivileged local user who can traverse a mounted malicious HFS+ volume can expose adjacent kernel heap data or trigger a kernel oops and filesystem failure.

The record

CVE
CVE-2025-40088
Published
Oct 30, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 30, 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 <42520df65bf67189541a425f7d36b0b3e7bd7844
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4bc081ba6c52b0c88c92701e3fbc33c7e2277afb
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4f5ab4a9c6abd8b0d713cc2b7b041bc10d70f241
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <586c75dfd1d265c4150f6529debb85c9d62e101f
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <603158d4efa98a13a746bd586c20f194f4a31ec8
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7ab44236b32ed41eb0636797e8e8e885a2f3b18a
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b47a75b6f762321f9eb6f31aab7bce47a37063b7
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ef250c3edd995d7bb5a5e5122ffad1c28a8686eb
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <42520df65bf67189541a425f7d36b0b3e7bd7844; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4bc081ba6c52b0c88c92701e3fbc33c7e2277afb; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4f5ab4a9c6abd8b0d713cc2b7b041bc10d70f241; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <586c75dfd1d265c4150f6529debb85c9d62e101f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <603158d4efa98a13a746bd586c20f194f4a31ec8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7ab44236b32ed41eb0636797e8e8e885a2f3b18a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b47a75b6f762321f9eb6f31aab7bce47a37063b7; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ef250c3edd995d7bb5a5e5122ffad1c28a8686eb; version=2.6.12

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.1Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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

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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