CVE-2025-39925

Description

In the Linux kernel, the following vulnerability has been resolved: can: j1939: implement NETDEV_UNREGISTER notification handler syzbot is reporting unregister_netdevice: waiting for vcan0 to become free. Usage count = 2 problem, for j1939 protocol did not have NETDEV_UNREGISTER notification handler for undoing changes made by j1939_sk_bind(). Commit 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct callback") expects that a call to j1939_priv_put() can be unconditionally delayed until j1939_sk_sock_destruct() is called. But we need to call j1939_priv_put() against an extra ref held by j1939_sk_bind() call (as a part of undoing changes made by j1939_sk_bind()) as soon as NETDEV_UNREGISTER notification fires (i.e. before j1939_sk_sock_destruct() is called via j1939_sk_release()). Otherwise, the extra ref on "struct j1939_priv" held by j1939_sk_bind() call prevents "struct net_device" from dropping the usage count to 1; making it impossible for unregister_netdevice() to continue. [mkl: remove space in front of label]

CVSS Metrics

• v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.15%• Percentile: 4%

Affected Systems

• chainguard•linux-aws-6.12

  < 6.12.76-r0 | < 6.12.69-r0 | < 6.12.77-r0 | < 6.12.63-r0 | < 6.12.71-r0 | < 6.12.74-r1 | < 6.12.77-r2 | < 6.12.68-r1 | < 6.12.62-r2 | < 6.12.74-r0 | < 6.12.65-r0 | < 6.12.67-r0 | < 6.12.77-r1 | < 6.12.65-r1 | < 6.12.72-r0 | < 6.12.80-r0 | < 6.12.66-r0 | < 6.12.65-r2 | < 6.12.68-r0 | < 6.12.70-r0 | < 6.12.62-r1 | < 6.12.72-r1 | < 6.12.78-r0

• chainguard•linux-azure-6.12

  < 6.12.62-r2 | < 6.12.68-r0 | < 6.12.65-r1 | < 6.12.63-r0 | < 6.12.65-r3 | < 6.12.62-r1 | < 6.12.66-r0 | < 6.12.65-r2 | < 6.12.77-r0 | < 6.12.69-r0 | < 6.12.80-r0 | < 6.12.77-r2 | < 6.12.78-r0 | < 6.12.70-r0 | < 6.12.77-r1 | < 6.12.76-r0 | < 6.12.67-r0 | < 6.12.65-r4 | < 6.12.71-r0 | < 6.12.72-r0 | < 6.12.74-r1 | < 6.12.74-r0

• chainguard•linux-gcp-6.12

  < 6.12.69-r0 | < 6.12.76-r0 | < 6.12.77-r0 | < 6.12.77-r1 | < 6.12.74-r0 | < 6.12.65-r2 | < 6.12.68-r0 | < 6.12.74-r1 | < 6.12.62-r2 | < 6.12.65-r1 | < 6.12.70-r0 | < 6.12.63-r0 | < 6.12.77-r2 | < 6.12.72-r0 | < 6.12.71-r0 | < 6.12.68-r1 | < 6.12.65-r0 | < 6.12.62-r1 | < 6.12.67-r0 | < 6.12.80-r0 | < 6.12.66-r0 | < 6.12.78-r0

• chainguard•linux-qemu-6.12

  < 6.12.77-r1 | < 6.12.72-r0 | < 6.12.77-r2 | < 6.12.68-r0 | < 6.12.65-r2 | < 6.12.66-r0 | < 6.12.70-r0 | < 6.12.69-r0 | < 6.12.74-r1 | < 6.12.65-r1 | < 6.12.71-r0 | < 6.12.78-r0 | < 6.12.77-r0 | < 6.12.74-r0 | < 6.12.67-r0 | < 6.12.76-r0 | < 6.12.80-r0

• chainguard•linux-vmware-6.12

  < 6.12.68-r0 | < 6.12.72-r0 | < 6.12.65-r2 | < 6.12.78-r0 | < 6.12.77-r1 | < 6.12.71-r0 | < 6.12.68-r1 | < 6.12.70-r0 | < 6.12.74-r1 | < 6.12.65-r1 | < 6.12.69-r0 | < 6.12.76-r0 | < 6.12.80-r0 | < 6.12.77-r0 | < 6.12.67-r0 | < 6.12.66-r0 | < 6.12.77-r2 | < 6.12.74-r0

• debian•linux

  all | all | < 6.1.187-1 | all | < 6.16.8-1

• ubuntu•linux

  all | all | all

• ubuntu•linux-allwinner-5.19

  all

• ubuntu•linux-aws

  all | all | all

• ubuntu•linux-aws-5.0

  all

• ubuntu•linux-aws-5.11

  all

• ubuntu•linux-aws-5.13

  all

• ubuntu•linux-aws-5.15

  all

• ubuntu•linux-aws-5.19

  all

• ubuntu•linux-aws-5.3

  all

• ubuntu•linux-aws-5.4

  all

• ubuntu•linux-aws-5.8

  all

• ubuntu•linux-aws-6.14

  all

• ubuntu•linux-aws-6.2

  all

• ubuntu•linux-aws-6.5

  all

• ubuntu•linux-aws-6.8

  all

• ubuntu•linux-aws-fips

  all

• ubuntu•linux-azure

  all | all | all | all

• ubuntu•linux-azure-5.11

  all

• ubuntu•linux-azure-5.13

  all

• ubuntu•linux-azure-5.15

  all

• ubuntu•linux-azure-5.19

  all

• ubuntu•linux-azure-5.3

  all

• ubuntu•linux-azure-5.4

  all

• ubuntu•linux-azure-5.8

  all

• ubuntu•linux-azure-6.11

  all

• ubuntu•linux-azure-6.14

  all

• ubuntu•linux-azure-6.2

  all

• ubuntu•linux-azure-6.5

  all

• ubuntu•linux-azure-6.8

  all

• ubuntu•linux-azure-edge

  all

• ubuntu•linux-azure-fde

  all | all | all | all

• ubuntu•linux-azure-fde-5.19

  all

• ubuntu•linux-azure-fde-6.14

  all

• ubuntu•linux-azure-fde-6.17

  all

• ubuntu•linux-azure-fde-6.2

  all

• ubuntu•linux-azure-fde-6.8

  all

• ubuntu•linux-azure-fips

  all

• ubuntu•linux-azure-nvidia

  all

• ubuntu•linux-azure-nvidia-6.14

  all

• ubuntu•linux-bluefield

  all | all

• ubuntu•linux-fips

  all

• ubuntu•linux-gcp

  all | all | all | all

• ubuntu•linux-gcp-5.11

  all

• ubuntu•linux-gcp-5.13

  all

Showing first 50 affected entries in server-rendered view.

References (13)

• https://git.kernel.org/stable/c/da9e8f429139928570407e8f90559b5d46c20262
• https://git.kernel.org/stable/c/7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a
• https://ubuntu.com/security/CVE-2025-39925
• https://www.cve.org/CVERecord?id=CVE-2025-39925
• https://git.kernel.org/linus/7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a
• https://security-tracker.debian.org/tracker/CVE-2025-39925
• https://git.kernel.org/stable/c/479d8a2aedcc1db16f14c1a8a9c74b5bdf18b9ac
• https://git.kernel.org/stable/c/2c88069fac2c792e228e6a4ae71c9b9b5b9a87a6
• https://git.kernel.org/stable/c/76957b618ce729c3bd1e782fbc9d9991af653925
• https://git.kernel.org/stable/c/4e154cb5e7681c2910e2dfa09f05e3469e333745
• https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39925.json
• https://nvd.nist.gov/vuln/detail/CVE-2025-39925
• https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git