CVE-2025-39743

Local kernel crash via retained inode pages

Published Sep 11, 2025 · Updated May 12, 2026

Improper input validation in Linux JFS allows local users to crash affected Linux and SIMATIC CN 4100 systems via a crafted inode. The JFS eviction path skips final page truncation when a disk-supplied inode has zero hard links, leaving cached pages that trigger a BUG_ON in clear_inode(). Exploitation requires low-privileged local access and a crafted JFS filesystem state; the documented consequence is a kernel crash.

CVSS severity7.8
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Linux JFS allows local users to crash affected Linux and SIMATIC CN 4100 systems via a crafted inode. The JFS eviction path skips final page truncation when a disk-supplied inode has zero hard links, leaving cached pages that trigger a BUG_ON in clear_inode(). Exploitation requires low-privileged local access and a crafted JFS filesystem state; the documented consequence is a kernel crash.

The record

CVE
CVE-2025-39743
Published
Sep 11, 2025
Updated
May 12, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 2025CVE publishedPublication date reported by the CVE source.
  2. May 12, 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=2.6.14
  2. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <1bb5cdc3e39f0c2b311fcb631258b7e60d3fb0d3
  3. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <2b1d5ca395a5fb170c3f885cd42c16179f7f54ec
  4. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <2d91b3765cd05016335cd5df5e5c6a29708ec058
  5. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <34d8e982bac48bdcca7524644a8825a580edce74
  6. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <5845b926c561b8333cd65169526eec357d7bb449
  7. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <89fff8e3d6710fc32507b8e19eb5afa9fb79b896
  8. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <8ed7275910fb7177012619864e04d3008763f3ea
  9. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <b5b471820c33365a8ccd2d463578bf4e47056c2c
  10. Affected versionversion=32983696a48a6c41d99f3eca82ba7510a552d843 <df3fd8daf278eca365f221749ae5b728e8382a04

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.14; version=32983696a48a6c41d99f3eca82ba7510a552d843 <1bb5cdc3e39f0c2b311fcb631258b7e60d3fb0d3; version=32983696a48a6c41d99f3eca82ba7510a552d843 <2b1d5ca395a5fb170c3f885cd42c16179f7f54ec; version=32983696a48a6c41d99f3eca82ba7510a552d843 <2d91b3765cd05016335cd5df5e5c6a29708ec058; version=32983696a48a6c41d99f3eca82ba7510a552d843 <34d8e982bac48bdcca7524644a8825a580edce74; version=32983696a48a6c41d99f3eca82ba7510a552d843 <5845b926c561b8333cd65169526eec357d7bb449; version=32983696a48a6c41d99f3eca82ba7510a552d843 <89fff8e3d6710fc32507b8e19eb5afa9fb79b896; version=32983696a48a6c41d99f3eca82ba7510a552d843 <8ed7275910fb7177012619864e04d3008763f3ea; version=32983696a48a6c41d99f3eca82ba7510a552d843 <b5b471820c33365a8ccd2d463578bf4e47056c2c; version=32983696a48a6c41d99f3eca82ba7510a552d843 <df3fd8daf278eca365f221749ae5b728e8382a04
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

7.0Siemens ProductCERTCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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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