CVE-2025-39782

CPU hang via missing checkpoint-loop rescheduling

Published Sep 11, 2025 · Updated Sep 11, 2025

Denial of service in the Linux kernel jbd2 checkpoint path allows local users to hang a CPU during sustained ext4 writeback. The jbd2_log_do_checkpoint() loop releases and reacquires j_list_lock but lacks an explicit cond_resched() call, relying on flush or buffer waits that do not always sleep. Triggering requires low-privileged local access and prolonged checkpoint contention; the reported consequence is a soft lockup that stalls a CPU.

CVSS severity5.5
Medium
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

Denial of service in the Linux kernel jbd2 checkpoint path allows local users to hang a CPU during sustained ext4 writeback. The jbd2_log_do_checkpoint() loop releases and reacquires j_list_lock but lacks an explicit cond_resched() call, relying on flush or buffer waits that do not always sleep. Triggering requires low-privileged local access and prolonged checkpoint contention; the reported consequence is a soft lockup that stalls a CPU.

The record

CVE
CVE-2025-39782
Published
Sep 11, 2025
Updated
Sep 11, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-413, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <26cb9aad94cb1811d8fae115594cc71fa3d91ab0
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3faac5e1d14c63260fd1bf789d96bde3ab3d9e54
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <41f40038de62e8306897cf6840791b268996432a
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <429d50cbaff45090d52a1ea850d5de8c14881ee7
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <84ff98c1ea19acd3f9389e4bb6061364e943f85e
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9d98cf4632258720f18265a058e62fde120c0151
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f683d611518d30334813eecf9a8c687453e2800e
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f7ee8fd689e6d534f9fd2494b9266f7998082e65

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <26cb9aad94cb1811d8fae115594cc71fa3d91ab0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3faac5e1d14c63260fd1bf789d96bde3ab3d9e54; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <41f40038de62e8306897cf6840791b268996432a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <429d50cbaff45090d52a1ea850d5de8c14881ee7; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <84ff98c1ea19acd3f9389e4bb6061364e943f85e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9d98cf4632258720f18265a058e62fde120c0151; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f683d611518d30334813eecf9a8c687453e2800e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f7ee8fd689e6d534f9fd2494b9266f7998082e65

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5UbuntuCVSS: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-413Improper Resource Locking
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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