CVE-2025-38687

Kernel memory corruption via dangling comedi wait queue

Published Sep 4, 2025 · Updated Aug 5, 2026

Use-after-free in Linux comedi and SIMATIC CN 4100 before V5.0 allows local users to corrupt kernel memory through device polling. The COMEDI_DEVCONFIG detach path frees a subdevice's async area while epoll entries still reference its wait_queue_head, leaving a dangling kernel pointer. Access to /dev/comediN is required, and a privileged detach or reconfiguration must then occur; exploitation can crash the kernel or enable memory disclosure and privilege escalation.

CVSS severity7.3
High
EPSS probability0.12%
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 Linux comedi and SIMATIC CN 4100 before V5.0 allows local users to corrupt kernel memory through device polling. The COMEDI_DEVCONFIG detach path frees a subdevice's async area while epoll entries still reference its wait_queue_head, leaving a dangling kernel pointer. Access to /dev/comediN is required, and a privileged detach or reconfiguration must then occur; exploitation can crash the kernel or enable memory disclosure and privilege escalation.

The record

CVE
CVE-2025-38687
Published
Sep 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-20, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 4, 2025CVE 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=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <017198079551a2a5cf61eae966af3c4b145e1f3b
  2. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <0f989f9d05492028afd2bded4b42023c57d8a76e
  3. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <35b6fc51c666fc96355be5cd633ed0fe4ccf68b2
  4. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <5724e82df4f9a4be62908362c97d522d25de75dd
  5. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <5c4a2ffcbd052c69bbf4680677d4c4eaa5a252d4
  6. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <71ca60d2e631cf9c63bcbc7017961c61ff04e419
  7. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <cd4286123d6948ff638ea9cd5818ae4796d5d252
  8. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <d85fac8729c9acfd72368faff1d576ec585e5c8f
  9. Affected versionversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <fe67122ba781df44a1a9716eb1dfd751321ab512
  10. Affected versionversion=3.14

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <017198079551a2a5cf61eae966af3c4b145e1f3b; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <0f989f9d05492028afd2bded4b42023c57d8a76e; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <35b6fc51c666fc96355be5cd633ed0fe4ccf68b2; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <5724e82df4f9a4be62908362c97d522d25de75dd; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <5c4a2ffcbd052c69bbf4680677d4c4eaa5a252d4; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <71ca60d2e631cf9c63bcbc7017961c61ff04e419; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <cd4286123d6948ff638ea9cd5818ae4796d5d252; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <d85fac8729c9acfd72368faff1d576ec585e5c8f; version=2f3fdcd7ce935f6f2899ceab57dc8fe5286db3e1 <fe67122ba781df44a1a9716eb1dfd751321ab512; version=3.14
Siemens · SIMATIC CN 4100version=0 <V5.0

Published CVSS scores

7.3Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
5.5Siemens ProductCERTCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
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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