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Response snapshot Nov 5, 2026, 23:11 UTC

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VulnerabilityCVE-2023-53522

Linux kernel: cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex

In the Linux kernel, the following vulnerability has been resolved: cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex syzbot is reporting circular locking dependency between cpu_hotplug_lock and freezer_mutex, for commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic") replaced atomic_inc() in freezer_apply_state() with static_branch_inc() which holds cpu_hotplug_lock.

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2023-53522 (opens a new tab)

What happened

In the Linux kernel, the following vulnerability has been resolved:

cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex

syzbot is reporting circular locking dependency between cpu_hotplug_lock and freezer_mutex, for commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic") replaced atomic_inc() in freezer_apply_state() with static_branch_inc() which holds cpu_hotplug_lock.

cpu_hotplug_lock => cgroup_threadgroup_rwsem => freezer_mutex

Continue reading

cgroup_file_write() { cgroup_procs_write() { __cgroup_procs_write() { cgroup_procs_write_start() { cgroup_attach_lock() { cpus_read_lock() { percpu_down_read(&cpu_hotplug_lock); } percpu_down_write(&cgroup_threadgroup_rwsem); } } cgroup_attach_task() { cgroup_migrate() { cgroup_migrate_execute() { freezer_attach() { mutex_lock(&freezer_mutex); (...snipped...) } } } } (...snipped...) } } }

freezer_mutex => cpu_hotplug_lock

cgroup_file_write() { freezer_write() { freezer_change_state() { mutex_lock(&freezer_mutex); freezer_apply_state() { static_branch_inc(&freezer_active) { static_key_slow_inc() { cpus_read_lock(); static_key_slow_inc_cpuslocked(); cpus_read_unlock(); } } } mutex_unlock(&freezer_mutex); } } }

Swap locking order by moving cpus_read_lock() in freezer_apply_state() to before mutex_lock(&freezer_mutex) in freezer_change_state().

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2023-53522 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 5). Linux kernel: cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex (CVE-2023-53522). https://kevwire.com/record/CVE-2023-53522

MLA

"Linux kernel: cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex (CVE-2023-53522)." KEVWire, 5 Nov. 2026, kevwire.com/record/CVE-2023-53522.

Chicago

KEVWire. "Linux kernel: cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex (CVE-2023-53522)." Last modified November 5, 2026. https://kevwire.com/record/CVE-2023-53522.

Evidence summary (plain text)

Linux kernel: cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex (Oct 1, 2025).
In the Linux kernel, the following vulnerability has been resolved:

cgroup,freezer: hold cpu_hotplug_lock before freezer_mutex

syzbot is reporting circular locking dependency between cpu_hotplug_lock
and freezer_mutex, for commit f5d39b020809 ("freezer,sched: Rewrite core
freezer logic") replaced atomic_inc() in freezer_apply_state() with
static_branch_inc() which holds cpu_hotplug_lock.
CVSS 7.8 (version 3.1; evidence as of Nov 5, 2026; https://nvd.nist.gov/vuln/detail/CVE-2023-53522).
Sources:
NVD CVE-2023-53522: https://nvd.nist.gov/vuln/detail/CVE-2023-53522
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T20:51:23.450Z&lastModEndDate=2026-11-05T22:25:57.582Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T20:16:05.862Z&lastModEndDate=2026-11-05T21:50:58.884Z&resultsPerPage=500&startIndex=500
Record ID: CVE-2023-53522.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 5, 2026, 22:25 UTC. Ingestion is not an independent editorial investigation.

NVD status: Analyzed. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail