CVE-2026-31598Network attack vector

Filesystem-operation hang via reversed OCFS2 locks

Published Apr 24, 2026 · Updated Apr 24, 2026

Deadlock in Linux Kernel OCFS2 allows remote attackers to hang filesystem operations via concurrent direct writes and unlinks. ocfs2_dio_end_io_write holds ip_alloc_sem before locking the orphan-directory inode, reversing ocfs2_unlink's order and deadlocking both paths. Reachability requires a writable OCFS2 volume and concurrent extending direct writes and unlink operations; remote exposure exists when the volume is exported through NFS.

CVSS severity7.5
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in Linux Kernel OCFS2 allows remote attackers to hang filesystem operations via concurrent direct writes and unlinks. ocfs2_dio_end_io_write holds ip_alloc_sem before locking the orphan-directory inode, reversing ocfs2_unlink's order and deadlocking both paths. Reachability requires a writable OCFS2 volume and concurrent extending direct writes and unlink operations; remote exposure exists when the volume is exported through NFS.

The record

CVE
CVE-2026-31598
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-667, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2b884d52273c60c298bd570163e8053657bbaff6
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bc0fb5c7d54c78be43a536df0e20dee32adb27d3
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e049f7a9bd80b7319590789ea5e1c523d6339d91
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f9fb1a7b635849322e1d7b7b6b26389778ec8e82

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2b884d52273c60c298bd570163e8053657bbaff6; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <bc0fb5c7d54c78be43a536df0e20dee32adb27d3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e049f7a9bd80b7319590789ea5e1c523d6339d91; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f9fb1a7b635849322e1d7b7b6b26389778ec8e82

Published CVSS scores

7.5kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-667Improper Locking
T1499.004Endpoint Denial of Service: Application 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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