VulnerabilityPublished 11 Sep 2025Updated 5 Nov 2026

CVE-2025-39782: Linux kernel · jbd2: prevent softlockup in jbd2_log_do_checkpoint()

Affects Linux kernelSource CVE Database V5

Compare

Not known to be exploited · fixed in f683d611518d30334813eecf9a8c687453e2800e : update Linux kernel when convenient.

Data as of 5 Nov 2026, 21:35 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-05.

Patch

Available – fixed in f683d611518d30334813eecf9a8c687453e2800e, f7ee8fd689e6d534f9fd2494b9266f7998082e65, 429d50cbaff45090d52a1ea850d5de8c14881ee7 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ f93ea411b73594f7d144855fd34278bcf34a9afc, < f683d611518d30334813eecf9a8c687453e2800e	Fixed in f683d611518d30334813eecf9a8c687453e2800e
LinuxLinux	Affected ≥ f93ea411b73594f7d144855fd34278bcf34a9afc, < f7ee8fd689e6d534f9fd2494b9266f7998082e65	Fixed in f7ee8fd689e6d534f9fd2494b9266f7998082e65
LinuxLinux	Affected ≥ f93ea411b73594f7d144855fd34278bcf34a9afc, < 429d50cbaff45090d52a1ea850d5de8c14881ee7	Fixed in 429d50cbaff45090d52a1ea850d5de8c14881ee7
LinuxLinux	Affected ≥ f93ea411b73594f7d144855fd34278bcf34a9afc, < 84ff98c1ea19acd3f9389e4bb6061364e943f85e	Fixed in 84ff98c1ea19acd3f9389e4bb6061364e943f85e
LinuxLinux	Affected ≥ f93ea411b73594f7d144855fd34278bcf34a9afc, < 41f40038de62e8306897cf6840791b268996432a	Fixed in 41f40038de62e8306897cf6840791b268996432a
LinuxLinux	Affected ≥ f93ea411b73594f7d144855fd34278bcf34a9afc, < 26cb9aad94cb1811d8fae115594cc71fa3d91ab0	Fixed in 26cb9aad94cb1811d8fae115594cc71fa3d91ab0

AI-suggested

A fix has been implemented and is available in the Linux kernel versions identified by the fixed commit hashes. Users should update their Linux kernel to a version that includes these fixes to prevent softlockups caused by this issue. No additional mitigation is required beyond applying the official patch.

Description

CVE-2025-39782 is a vulnerability in the Linux kernel's jbd2 subsystem that can cause a CPU softlockup. The issue arises because the jbd2_log_do_checkpoint() function does not explicitly call cond_resched() to yield the CPU during prolonged operations, relying instead on potentially non-sleeping functions to trigger rescheduling. This can lead to the kernel becoming unresponsive on affected CPUs. The vulnerability has been fixed by adding an explicit cond_resched() call in jbd2_log_do_checkpoint().

Impact

This vulnerability can cause a CPU softlockup, where the CPU becomes stuck processing kernel code for an extended period (e.g., 156 seconds), leading to system unresponsiveness or degraded performance. It affects system stability but does not directly expose data or allow privilege escalation. There are no known exploits in the wild.

Summary

The Linux kernel's jbd2 subsystem manages journaling for filesystems like ext4. Both jbd2_log_do_checkpoint() and jbd2_journal_shrink_checkpoint_list() periodically release a lock (j_list_lock) to avoid long hold times. While jbd2_journal_shrink_checkpoint_list() explicitly calls cond_resched() to prevent softlockups, jbd2_log_do_checkpoint() relies on functions that may not sleep to trigger rescheduling. If these functions do not sleep, the CPU can become stuck in a softlockup state, as observed in kernel logs. The fix involves explicitly calling cond_resched() within jbd2_log_do_checkpoint() to ensure the scheduler can preempt the task and avoid CPU lockup.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Nov 2026, 21:35 UTC

Technical details

References

Community reviews

Related threats