CVE-2025-39721

Kernel crash via pending QAT workqueue callback

Published Sep 5, 2025 · Updated Sep 5, 2025

Use-after-free in the Linux QAT driver allows local users to crash affected kernels by racing device-driver unload with PM work. A PM interrupt can queue pm_bh_handler on the shared qat_misc_wq just before a device-specific module unloads, leaving the callback to dereference freed driver memory. Exploitation requires local low-privilege access, repeated loading and unloading of a QAT device driver, and timing the unload against the interrupt; the documented consequence is a page fault and kernel crash.

CVSS severity5.5
Medium
EPSS probability0.14%
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 QAT driver allows local users to crash affected kernels by racing device-driver unload with PM work. A PM interrupt can queue pm_bh_handler on the shared qat_misc_wq just before a device-specific module unloads, leaving the callback to dereference freed driver memory. Exploitation requires local low-privilege access, repeated loading and unloading of a QAT device driver, and timing the unload against the interrupt; the documented consequence is a page fault and kernel crash.

The record

CVE
CVE-2025-39721
Published
Sep 5, 2025
Updated
Sep 5, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 2025Record 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=5.18
  2. Affected versionversion=e5745f34113b758b45d134dec04a7df94dc67131 <3d4df408ba9bad2b205c7fb8afc1836a6a4ca88a
  3. Affected versionversion=e5745f34113b758b45d134dec04a7df94dc67131 <5858448a6c65d8ee3f8600570d3ce19febcb33be
  4. Affected versionversion=e5745f34113b758b45d134dec04a7df94dc67131 <e59a52e429e13df3feb34f4853a8e36d121ed937
  5. Affected versionversion=e5745f34113b758b45d134dec04a7df94dc67131 <fe546f5c50fc474daca6bee72caa7ab68a74c33d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.18; version=e5745f34113b758b45d134dec04a7df94dc67131 <3d4df408ba9bad2b205c7fb8afc1836a6a4ca88a; version=e5745f34113b758b45d134dec04a7df94dc67131 <5858448a6c65d8ee3f8600570d3ce19febcb33be; version=e5745f34113b758b45d134dec04a7df94dc67131 <e59a52e429e13df3feb34f4853a8e36d121ed937; version=e5745f34113b758b45d134dec04a7df94dc67131 <fe546f5c50fc474daca6bee72caa7ab68a74c33d

Published CVSS scores

5.5NIST NVDCVSS: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 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
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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