CVE-2025-39736 | mm/kmemleak: avoid deadlock by moving pr_warn() outside kmemleak_lock

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.

Published: 2025-09-11 Last update: 2026-06-17 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-39736 is rated Low Risk (22.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.12%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-39736

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.03% 0.12% +0.09%
2 2025-09-12 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-39736

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2025-39736

GitHub Security Advisory for CVE-2025-39736

GHSA-7g87-hx7m-ppg8 · Severity: medium — In the Linux kernel, the following vulnerability has been resolved: mm/kmemleak: avoid deadlock...

OS Trackers for CVE-2025-39736

vendor priority summary link
debian not yet assigned CVE-2025-39736 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-39736
redhat low — https://access.redhat.com/security/cve/CVE-2025-39736
suse medium CVE-2025-39736 severity moderate: SUSE including 26 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 317 product×package rows across 60 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Availability Extension 15 SP3, … (60 product lines)): Known Not Affected 317. https://www.suse.com/security/cve/CVE-2025-39736/
ubuntu medium CVE-2025-39736 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1414 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1017, ignored 176, released 150, not-affected 40, needed 28, needs-triage 2, pending 1. https://ubuntu.com/security/CVE-2025-39736

Affected software / configurations for CVE-2025-39736

Vendor Product Version Raw CPE
linux linux_kernel >= 5.4, < 5.4.297 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.5, < 5.10.241 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.190 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.149 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.103 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.43 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.15.11 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.16, < 6.16.2 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 6.17 cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2025-39736

URL Tags
https://git.kernel.org/stable/c/08f70be5e406ce47c822f2dd11c1170ca259605b Patch
https://git.kernel.org/stable/c/1da95d3d4b7b1d380ebd87b71a61e7e6aed3265d Patch
https://git.kernel.org/stable/c/47b0f6d8f0d2be4d311a49e13d2fd5f152f492b2 Patch
https://git.kernel.org/stable/c/4b0151e1d468eb2667c37b7af99b3c075072d334 Patch
https://git.kernel.org/stable/c/62879faa8efe8d8a9c7bf7606ee9c068012d7dac Patch
https://git.kernel.org/stable/c/a0854de00ce2ee27edf39037e7836ad580eb3350 Patch
https://git.kernel.org/stable/c/a181b228b37a6a5625dad2bb4265bb7abb673e9f Patch
https://git.kernel.org/stable/c/c7b6ea0ede687e7460e593c5ea478f50aa41682a Patch
https://git.kernel.org/stable/c/f249d32bb54876b4b6c3ae071af8ddca77af390b Patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Mailing List Third Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-032379.html
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