CVE-2025-39835

Kernel crash via mishandled xattr disk error

Published Sep 16, 2025 · Updated Sep 16, 2025

A null-pointer dereference in Linux XFS kernels starting at 5.9 allows local users to crash the kernel during an xattr lookup. xfs_attr_leaf_get treats a disk ENODATA result as a missing attribute and passes the resulting null buffer pointer to xfs_trans_brelse. Triggering the fault requires a medium error on a specific XFS metadata block and storage-level access; the bounded consequence is a kernel oops and service interruption.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A null-pointer dereference in Linux XFS kernels starting at 5.9 allows local users to crash the kernel during an xattr lookup. xfs_attr_leaf_get treats a disk ENODATA result as a missing attribute and passes the resulting null buffer pointer to xfs_trans_brelse. Triggering the fault requires a medium error on a specific XFS metadata block and storage-level access; the bounded consequence is a kernel oops and service interruption.

The record

CVE
CVE-2025-39835
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2025Record 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=07120f1abdff80f3d1351f733661abe28d609535 <157ddfb05961c68ab7d457a462822a698e4e4bf4
  2. Affected versionversion=07120f1abdff80f3d1351f733661abe28d609535 <39fc2742ca14f7fbc621ce9b43bcbd00248cb9a8
  3. Affected versionversion=07120f1abdff80f3d1351f733661abe28d609535 <90bae69c2959c39912f0c2f07a9a7894f3fc49f5
  4. Affected versionversion=07120f1abdff80f3d1351f733661abe28d609535 <ae668cd567a6a7622bc813ee0bb61c42bed61ba7
  5. Affected versionversion=07120f1abdff80f3d1351f733661abe28d609535 <d3cc7476b89fb45b7e00874f4f56f6b928467c60
  6. Affected versionversion=07120f1abdff80f3d1351f733661abe28d609535 <dcdf36f1b67884c722abce9b8946e34ffb9f67c8
  7. Affected versionversion=07120f1abdff80f3d1351f733661abe28d609535 <e358d4b6225e4c1eb208686a05e360ef8df59e07
  8. Affected versionversion=5.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=07120f1abdff80f3d1351f733661abe28d609535 <157ddfb05961c68ab7d457a462822a698e4e4bf4; version=07120f1abdff80f3d1351f733661abe28d609535 <39fc2742ca14f7fbc621ce9b43bcbd00248cb9a8; version=07120f1abdff80f3d1351f733661abe28d609535 <90bae69c2959c39912f0c2f07a9a7894f3fc49f5; version=07120f1abdff80f3d1351f733661abe28d609535 <ae668cd567a6a7622bc813ee0bb61c42bed61ba7; version=07120f1abdff80f3d1351f733661abe28d609535 <d3cc7476b89fb45b7e00874f4f56f6b928467c60; version=07120f1abdff80f3d1351f733661abe28d609535 <dcdf36f1b67884c722abce9b8946e34ffb9f67c8; version=07120f1abdff80f3d1351f733661abe28d609535 <e358d4b6225e4c1eb208686a05e360ef8df59e07; version=5.9

Published CVSS scores

7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

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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