CVE-2025-40306

Kernel crash via unterminated xattr key scan

Published Dec 8, 2025 · Updated Aug 5, 2026

Buffer over-read in OrangeFS xattr handling in Linux allows local users to crash the kernel through xattr syscalls. The xattr_key helper tests the key pointer instead of the pointed-to byte, so it scans beyond the terminating null; cache insertion also hashes an already hashed key into the wrong bucket, leaking each negative xattr allocation. Any local user with read access to a file on a mounted OrangeFS filesystem can trigger a kernel oops, hang processes, corrupt OrangeFS files, or exhaust memory.

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

What happened

Buffer over-read in OrangeFS xattr handling in Linux allows local users to crash the kernel through xattr syscalls. The xattr_key helper tests the key pointer instead of the pointed-to byte, so it scans beyond the terminating null; cache insertion also hashes an already hashed key into the wrong bucket, leaking each negative xattr allocation. Any local user with read access to a file on a mounted OrangeFS filesystem can trigger a kernel oops, hang processes, corrupt OrangeFS files, or exhaust memory.

The record

CVE
CVE-2025-40306
Published
Dec 8, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 8, 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=4.6
  2. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <025e880759c279ec64d0f754fe65bf45961da864
  3. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <15afebb9597449c444801d1ff0b8d8b311f950ab
  4. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <9127d1e90c90e5960c8bc72a4ce2c209691a7021
  5. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <bc812574de633cf9a9ad6974490e45f6a4bb5126
  6. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <c2ca015ac109fd743fdde27933d59dc5ad46658e
  7. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <c6564ff6b53c9a8dc786b6f1c51ae7688273f931
  8. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <e09a096104fc65859422817fb2211f35855983fe
  9. Affected versionversion=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <ef892d2bf4f3fa2c8de1677dd307e678bdd3d865

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.6; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <025e880759c279ec64d0f754fe65bf45961da864; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <15afebb9597449c444801d1ff0b8d8b311f950ab; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <9127d1e90c90e5960c8bc72a4ce2c209691a7021; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <bc812574de633cf9a9ad6974490e45f6a4bb5126; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <c2ca015ac109fd743fdde27933d59dc5ad46658e; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <c6564ff6b53c9a8dc786b6f1c51ae7688273f931; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <e09a096104fc65859422817fb2211f35855983fe; version=f7ab093f74bf638ed98fd1115f3efa17e308bb7f <ef892d2bf4f3fa2c8de1677dd307e678bdd3d865

Published CVSS scores

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

T1499.004Application or System Exploitation

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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