CVE-2024-39468Network attack vector

System hang via nested SMB session lock

Published Jun 25, 2024 · Updated Aug 5, 2026

Improper locking in the Linux SMB client and affected Siemens products allows attackers to hang systems during SMB session cleanup. smb2_find_smb_tcon() calls cifs_put_smb_ses() while holding cifs_tcp_ses_lock, whose nested cleanup path can reacquire that lock and deadlock. The trigger is undisclosed; published assessments disagree between unauthenticated network reachability and local low-privileged access, but report availability impact only.

CVSS severity7.5
High
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in the Linux SMB client and affected Siemens products allows attackers to hang systems during SMB session cleanup. smb2_find_smb_tcon() calls cifs_put_smb_ses() while holding cifs_tcp_ses_lock, whose nested cleanup path can reacquire that lock and deadlock. The trigger is undisclosed; published assessments disagree between unauthenticated network reachability and local low-privileged access, but report availability impact only.

The record

CVE
CVE-2024-39468
Published
Jun 25, 2024
Updated
Aug 5, 2026
Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
Classifications
CWE-20, CWE-667, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SIMATIC S7-1500 TM MFP - GNU/Linux subsystemversion=0 <*
The Linux Kernel Organization · Linuxversion=5.14; version=78ebec450ef4f0720c592638d92bad679d75d7ce <b055752675cd1d1db4ac9c2750db3dc3e89ea261; version=e695a9ad0305af6e8b0cbc24a54976ac2120cbb3 <02c418774f76a0a36a6195c9dbf8971eb4130a15; version=e695a9ad0305af6e8b0cbc24a54976ac2120cbb3 <21f5dd36e655d25a7b45b61c1e537198b671f720; version=e695a9ad0305af6e8b0cbc24a54976ac2120cbb3 <225de871ddf994f69a57f035709cad9c0ab8615a; version=e695a9ad0305af6e8b0cbc24a54976ac2120cbb3 <8d0f5f1ccf675454a833a573c53830a49b7d1a47; version=e695a9ad0305af6e8b0cbc24a54976ac2120cbb3 <b09b556e48968317887a11243a5331a7bc00ece5
Siemens · SCALANCE XCM/XRM/XCH/XRH-300 familyversion=0 <V3.1
Siemens · RUGGEDCOM RST2428Pversion=0 <V3.1

Published CVSS scores

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5Linux Kernel CVE TeamCVSS: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-20Improper Input Validation
CWE-667Improper Locking
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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