CVE-2023-53656

CPU-hotplug hang via stale online-CPU mask

Published Oct 7, 2025 · Updated Oct 7, 2025

Denial of service in the Linux HiSilicon PCIe PMU driver allows local users to hang CPU hotplug through a stale online-CPU mask. During hisi_pcie_pmu_offline_cpu, cpu_online_mask still includes the departing CPU, so perf context migration can target that CPU and block on a mutex. Reachability requires the HiSilicon PCIe PMU driver and CPU teardown; the observed consequence is an indefinitely blocked CPU-hotplug task.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux HiSilicon PCIe PMU driver allows local users to hang CPU hotplug through a stale online-CPU mask. During hisi_pcie_pmu_offline_cpu, cpu_online_mask still includes the departing CPU, so perf context migration can target that CPU and block on a mutex. Reachability requires the HiSilicon PCIe PMU driver and CPU teardown; the observed consequence is an indefinitely blocked CPU-hotplug task.

The record

CVE
CVE-2023-53656
Published
Oct 7, 2025
Updated
Oct 7, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 7, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 7, 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=5.17
  2. Affected versionversion=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <7a6a9f1c5a0a875a421db798d4b2ee022dc1ee1a
  3. Affected versionversion=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <b64569897d86b611befbb895d815280fea94e1ed
  4. Affected versionversion=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <be9c8c9c84b6d25a7b7d39954030aba6f759feb6
  5. Affected versionversion=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <f564e543a43d0f1cabac791672c8a6fc78ce12d0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.17; version=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <7a6a9f1c5a0a875a421db798d4b2ee022dc1ee1a; version=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <b64569897d86b611befbb895d815280fea94e1ed; version=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <be9c8c9c84b6d25a7b7d39954030aba6f759feb6; version=8404b0fbc7fbd42e5c5d28cdedd450e70829c77a <f564e543a43d0f1cabac791672c8a6fc78ce12d0

Published CVSS scores

4.4Red HatCVSS:3.1/AV:L/AC:L/PR:H/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

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

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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