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CVE-2025-39737· NVD / CVE Program· CNA Linux

mm/kmemleak: avoid soft lockup in __kmemleak_do_cleanup()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 1ef72a7fedc5bca70e8cc980985790de10d407aa, 8d2d22a55ffe35c38e69795468a7addd1a80e9ce, 926092268efdf1ed7b55cf486356c74a9e7710d1; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1.

Low priority for now. Upgrade to Linux Linux 1ef72a7fedc5bca70e8cc980985790de10d407aa, 8d2d22a55ffe35c38e69795468a7addd1a80e9ce, 926092268efdf1ed7b55cf486356c74a9e7710d1; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: mm/kmemleak: avoid soft lockup in __kmemleak_do_cleanup() A soft lockup warning was observed on a relative small system x86-64 system with 16 GB of memory when running a debug kernel with kmemleak enabled. watchdog: BUG: soft lockup - CPU#8 stuck for 33s! [kworker/8:1:134] The test system was running a workload with hot unplug happening in parallel. Then kemleak decided to disable itself due to its inability to allocate more kmemleak objects. The debug kernel has its CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE set to 40,000. The soft lockup happened in kmemleak_do_cleanup() when the existing kmemleak objects were being removed and deleted one-by-one in a loop via a workqueue. In this particular case, there are at least 40,000 objects that need to be processed and given the slowness of a debug kernel and the fact that a raw_spinlock has to be acquired and released in __delete_object(), it could take a while to properly handle all these objects. As kmemleak has been disabled in this case, the object removal and deletion process can be further optimized as locking isn't really needed. However, it is probably not worth the effort to optimize for such an edge case that should rarely happen. So the simple solution is to call cond_resched() at periodic interval in the iteration loop to avoid soft lockup.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Sep 11, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 6th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux11.0
  • linux linux kernel5.5 and later · before 5.10.241
  • linux linux kernel5.11 and later · before 5.15.190
  • linux linux kernel5.16 and later · before 6.1.149
  • linux linux kernel6.2 and later · before 6.6.103
  • linux linux kernel5.4.1 and later · before 5.4.297
  • linux linux kernel6.13 and later · before 6.15.11
  • linux linux kernel6.16 and later · before 6.16.2
  • linux linux kernel6.7 and later · before 6.12.43
  • linux linux kernel5.4
  • linux linux kernel6.17

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.4affected
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before 9f1f4e95031f84867c5821540466d62f88dab8caaffected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before 1ef72a7fedc5bca70e8cc980985790de10d407aaaffected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before a04de4c40aab9b338dfa989cf4aec70fd187eeb2affected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before f014c10d190b92aad366e56b445daffcd1c075e4affected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before e21a3ddd58733ce31afcb1e5dc3cb80a4b5bc29baffected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before 8d2d22a55ffe35c38e69795468a7addd1a80e9ceaffected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before 926092268efdf1ed7b55cf486356c74a9e7710d1affected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before 9b80430c194e4a114dc663c1025d56b4f3d0153daffected · git
    • 2abd839aa7e615f2bbc50c8ba7deb9e40d186768 and later · before d1534ae23c2b6be350c8ab060803fbf6e9682adcaffected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.153-16.1.153-1
Debian:13linuxbefore 6.12.43-16.12.43-1
Debian:14linuxbefore 6.16.3-16.16.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-39734Sep 7, 2025 · Revert "fs/ntfs3: Replace inode_trylock with inode_lock"
    22Monitor
  • ← EarlierCVE-2025-39736Sep 11, 2025 · mm/kmemleak: avoid deadlock by moving pr_warn() outside kmemleak_lock
    22Monitor
  • Later →CVE-2025-39738Sep 11, 2025 · btrfs: do not allow relocation of partially dropped subvolumes
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1ef72a7fedc5bca70e8cc980985790de10d407aaVendor (CNA)
Linux Linux8d2d22a55ffe35c38e69795468a7addd1a80e9ceVendor (CNA)
Linux Linux926092268efdf1ed7b55cf486356c74a9e7710d1Vendor (CNA)
Linux Linux9b80430c194e4a114dc663c1025d56b4f3d0153dVendor (CNA)
Linux Linux9f1f4e95031f84867c5821540466d62f88dab8caVendor (CNA)
Linux Linuxa04de4c40aab9b338dfa989cf4aec70fd187eeb2Vendor (CNA)
Linux Linuxd1534ae23c2b6be350c8ab060803fbf6e9682adcVendor (CNA)
Linux Linuxe21a3ddd58733ce31afcb1e5dc3cb80a4b5bc29bVendor (CNA)
Linux Linuxf014c10d190b92aad366e56b445daffcd1c075e4Vendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.153-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-401 · Missing Release of Memory after Effective Lifetime

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (11 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records