CVE-2025-38684

Kernel crash via inconsistent ETS band cleanup

Published Sep 4, 2025 · Updated May 23, 2026

NULL-pointer dereference in Linux ETS queue scheduling allows local privileged users to crash the kernel while changing a qdisc configuration. ets_qdisc_change assigns the new q->nbands value before purging obsolete DWRR queues, so cleanup helpers interpret the old classes with inconsistent band state. The path requires high local privileges to reconfigure qdiscs; successful triggering interrupts the Linux host or affected SIMATIC CN 4100 appliance.

CVSS severity5.2
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 ETS queue scheduling allows local privileged users to crash the kernel while changing a qdisc configuration. ets_qdisc_change assigns the new q->nbands value before purging obsolete DWRR queues, so cleanup helpers interpret the old classes with inconsistent band state. The path requires high local privileges to reconfigure qdiscs; successful triggering interrupts the Linux host or affected SIMATIC CN 4100 appliance.

The record

CVE
CVE-2025-38684
Published
Sep 4, 2025
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 4, 2025CVE publishedPublication date reported by the CVE source.
  2. May 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3b290923ad2b23596208c1e29520badef4356a43
  2. Affected versionversion=5.4.296 <5.5
  3. Affected versionversion=5.6
  4. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <5b3b346bc4c2aa2c428735438a11989d251f32f1
  5. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <84a24fb446ee07b22b64aae6f0e3f4a38266310a
  6. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <87c6efc5ce9c126ae4a781bc04504b83780e3650
  7. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <970c1c731c4ede46d05f5b0355724d1e400cfbca
  8. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <97ec167cd2e8a81a2d87331a2ed92daf007542c8
  9. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <bdfddcde86e8b9245d9c0c2efe2b6fe8dcf6bf41
  10. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <be9692dafdfb36d9c43afd9d4e1d9d9ba8e7b51b
  11. Affected versionversion=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <d69f4a258cd91b3bcef7089eb0401005aae2aed5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=3b290923ad2b23596208c1e29520badef4356a43; version=5.4.296 <5.5; version=5.6; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <5b3b346bc4c2aa2c428735438a11989d251f32f1; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <84a24fb446ee07b22b64aae6f0e3f4a38266310a; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <87c6efc5ce9c126ae4a781bc04504b83780e3650; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <970c1c731c4ede46d05f5b0355724d1e400cfbca; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <97ec167cd2e8a81a2d87331a2ed92daf007542c8; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <bdfddcde86e8b9245d9c0c2efe2b6fe8dcf6bf41; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <be9692dafdfb36d9c43afd9d4e1d9d9ba8e7b51b; version=dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 <d69f4a258cd91b3bcef7089eb0401005aae2aed5
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

5.2Siemens ProductCERTCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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