CVE-2024-26958

Kernel memory corruption via double-completed NFS writes

Published May 1, 2024 · Updated Aug 5, 2026

Use-after-free in the Linux kernel allows local users to corrupt kernel memory through overlapping direct NFS write requests. While asynchronous commits are still being submitted, nfs_direct_write_schedule_work can observe an early completion and call nfs_direct_write_complete twice on the same nfs_direct_request. Triggering the race requires low-privileged local access and overlapping NFS commits; observed stress testing produced a refcount underflow and use-after-free warning.

CVSS severity7.8
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux kernel allows local users to corrupt kernel memory through overlapping direct NFS write requests. While asynchronous commits are still being submitted, nfs_direct_write_schedule_work can observe an early completion and call nfs_direct_write_complete twice on the same nfs_direct_request. Triggering the race requires low-privileged local access and overlapping NFS commits; observed stress testing produced a refcount underflow and use-after-free warning.

The record

CVE
CVE-2024-26958
Published
May 1, 2024
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=0 <*

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SIMATIC S7-1500 TM MFP - GNU/Linux subsystemversion=0 <*
The Linux Kernel Organization · Linuxversion=4.5; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <17f46b803d4f23c66cacce81db35fef3adb8f2af; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <1daf52b5ffb24870fbeda20b4967526d8f9e12ab; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <3abc2d160ed8213948b147295d77d44a22c88fa3; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <4595d90b5d2ea5fa4d318d13f59055aa4bf3e7f5; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <6cd3f13aaa62970b5169d990e936b2e96943bc6a; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <80d24b308b7ee7037fc90d8ac99f6f78df0a256f; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <cf54f66e1dd78990ec6b32177bca7e6ea2144a95; version=af7cf057933f01dc7f33ddfb5e436ad598ed17ad <e25447c35f8745337ea8bc0c9697fcac14df8605

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8Siemens ProductCERTCVSS: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

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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-416Use After Free
T1068Exploitation for Privilege Escalation

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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