CVE-2023-4385

System crash via unchecked JFS metapage write

Published Aug 16, 2023 · Updated Nov 20, 2025

NULL pointer dereference in Linux kernel JFS 5.18.19 and earlier allows local users to crash the system during block freeing. When dtSearch allocation fails, dbFree can receive zero nblocks, leave mp NULL, and pass it to write_metapage without a NULL check. A low-privileged local user must reach the block-freeing path on a system with JFS enabled; triggering the flaw causes a kernel crash, with no reported confidentiality or integrity impact.

CVSS severity5.5
Medium
EPSS probability0.23%
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 JFS 5.18.19 and earlier allows local users to crash the system during block freeing. When dtSearch allocation fails, dbFree can receive zero nblocks, leave mp NULL, and pass it to write_metapage without a NULL check. A low-privileged local user must reach the block-freeing path on a system with JFS enabled; triggering the flaw causes a kernel crash, with no reported confidentiality or integrity impact.

The record

CVE
CVE-2023-4385
Published
Aug 16, 2023
Updated
Nov 20, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 16, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 20, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5Red Hat, Inc.CVSS: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 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-476NULL Pointer Dereference
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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