CVE-2025-39736 Affecting linux-6.1 package, versions <6.1.153-1~deb11u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.05% (15th percentile)

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  • Snyk IDSNYK-DEBIAN11-LINUX61-13542127
  • published14 Oct 2025
  • disclosed11 Sept 2025

Introduced: 11 Sep 2025

CVE-2025-39736  (opens in a new tab)

How to fix?

Upgrade Debian:11 linux-6.1 to version 6.1.153-1~deb11u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.1 package and not the linux-6.1 package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1