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CVE-2025-39736· NVD / CVE Program· CNA Linux

mm/kmemleak: avoid deadlock by moving pr_warn() outside kmemleak_lock

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: 0.13% (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 08f70be5e406ce47c822f2dd11c1170ca259605b, 1da95d3d4b7b1d380ebd87b71a61e7e6aed3265d, 47b0f6d8f0d2be4d311a49e13d2fd5f152f492b2; 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 08f70be5e406ce47c822f2dd11c1170ca259605b, 1da95d3d4b7b1d380ebd87b71a61e7e6aed3265d, 47b0f6d8f0d2be4d311a49e13d2fd5f152f492b2; 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 deadlock by moving pr_warn() outside kmemleak_lock When netpoll is enabled, calling pr_warn_once() while holding kmemleak_lock in mem_pool_alloc() can cause a deadlock due to lock inversion with the netconsole subsystem. This occurs because pr_warn_once() may trigger netpoll, which eventually leads to __alloc_skb() and back into kmemleak code, attempting to reacquire kmemleak_lock. This is the path for the deadlock. mem_pool_alloc() -> raw_spin_lock_irqsave(&kmemleak_lock, flags); -> pr_warn_once() -> netconsole subsystem -> netpoll -> __alloc_skb -> __create_object -> raw_spin_lock_irqsave(&kmemleak_lock, flags); Fix this by setting a flag and issuing the pr_warn_once() after kmemleak_lock is released.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Sep 11, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 2th 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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-39736

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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 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 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
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before c7b6ea0ede687e7460e593c5ea478f50aa41682aaffected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before 4b0151e1d468eb2667c37b7af99b3c075072d334affected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before f249d32bb54876b4b6c3ae071af8ddca77af390baffected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before 62879faa8efe8d8a9c7bf7606ee9c068012d7dacaffected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before 1da95d3d4b7b1d380ebd87b71a61e7e6aed3265daffected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before a0854de00ce2ee27edf39037e7836ad580eb3350affected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before 08f70be5e406ce47c822f2dd11c1170ca259605baffected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before a181b228b37a6a5625dad2bb4265bb7abb673e9faffected · git
    • c5665868183fec689dbab9fb8505188b2c4f0757 and later · before 47b0f6d8f0d2be4d311a49e13d2fd5f152f492b2affected · 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-2025-39733Sep 7, 2025 · team: replace team lock with rtnl lock
    22Monitor
  • ← EarlierCVE-2025-39734Sep 7, 2025 · Revert "fs/ntfs3: Replace inode_trylock with inode_lock"
    22Monitor
  • Later →CVE-2025-39737Sep 11, 2025 · mm/kmemleak: avoid soft lockup in __kmemleak_do_cleanup()
    22Monitor

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 Linux08f70be5e406ce47c822f2dd11c1170ca259605bVendor (CNA)
Linux Linux1da95d3d4b7b1d380ebd87b71a61e7e6aed3265dVendor (CNA)
Linux Linux47b0f6d8f0d2be4d311a49e13d2fd5f152f492b2Vendor (CNA)
Linux Linux4b0151e1d468eb2667c37b7af99b3c075072d334Vendor (CNA)
Linux Linux62879faa8efe8d8a9c7bf7606ee9c068012d7dacVendor (CNA)
Linux Linuxa0854de00ce2ee27edf39037e7836ad580eb3350Vendor (CNA)
Linux Linuxa181b228b37a6a5625dad2bb4265bb7abb673e9fVendor (CNA)
Linux Linuxc7b6ea0ede687e7460e593c5ea478f50aa41682aVendor (CNA)
Linux Linuxf249d32bb54876b4b6c3ae071af8ddca77af390bVendor (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-667 · Improper Locking

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.

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