CVE-2025-39842

Kernel crash via OCFS2 journal null dereference

Published Sep 19, 2025 · Updated Sep 19, 2025

NULL-pointer dereference in Linux kernel OCFS2 allows local users to crash the system during an OCFS2 filesystem unmount. After ocfs2_journal_shutdown() clears osb->journal, the dismount cleanup path dereferences it while calling jbd2_journal_release_jbd_inode(). Local low-privileged access and an OCFS2 dismount are required, and the reported consequence is a kernel crash rather than data access or modification.

CVSS severity5.5
Medium
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

NULL-pointer dereference in Linux kernel OCFS2 allows local users to crash the system during an OCFS2 filesystem unmount. After ocfs2_journal_shutdown() clears osb->journal, the dismount cleanup path dereferences it while calling jbd2_journal_release_jbd_inode(). Local low-privileged access and an OCFS2 dismount are required, and the reported consequence is a kernel crash rather than data access or modification.

The record

CVE
CVE-2025-39842
Published
Sep 19, 2025
Updated
Sep 19, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 19, 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=5.16
  2. Affected versionversion=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <42c415c53ad2065088cc411d08925effa5b3d255
  3. Affected versionversion=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <85e66331b60601d903cceaf8c10a234db863cd78
  4. Affected versionversion=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <e9188f66e94955431ddbe2cd1cdf8ff2bb486abf
  5. Affected versionversion=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <f46e8ef8bb7b452584f2e75337b619ac51a7cadf
  6. Affected versionversion=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <f4a917e6cd6c798f7adf39907f117fc754db1283

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.16; version=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <42c415c53ad2065088cc411d08925effa5b3d255; version=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <85e66331b60601d903cceaf8c10a234db863cd78; version=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <e9188f66e94955431ddbe2cd1cdf8ff2bb486abf; version=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <f46e8ef8bb7b452584f2e75337b619ac51a7cadf; version=da5e7c87827e8caa6a1eeec6d95dcf74ab592a01 <f4a917e6cd6c798f7adf39907f117fc754db1283

Published CVSS scores

5.5NIST NVDCVSS: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

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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