What is CVE-2025-39925?

CVE-2025-39925 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 5.4 onward and patched in 6.16.8 and 6.17. CVE-2025-39925 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2025-39925?

CVE-2025-39925 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2025-39925?

Yes, CVE-2025-39925 has been patched. Fixed versions include 6.16.8 and 6.17. If you are running Linux kernel 5.4 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2025-39925 actively exploited?

CVE-2025-39925 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2025-39925

Medium

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]

Package Linux Kernel

Published 2025-10-01

Last modified 2026-01-14

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Affected versions

Linux kernel versions 5.4 and later are affected. Fixed in 6.16.8, 6.17 and their respective stable series.

Affected from

≥ 5.4

Fixed in

✓ 6.16.8 6.16.x ✓ 6.17

References

The following references provide additional information about CVE-2025-39925 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a
Patch
Kernel patch commit
https://git.kernel.org/stable/c/da9e8f429139928570407e8f90559b5d46c20262
Patch

Details

CVE ID CVE-2025-39925

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2025-10-01

Modified 2026-01-14

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2025-39925?

CVE-2025-39925 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 5.4 onward and has been patched in 6.16.8 and 6.17. CVE-2025-39925 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2025-39925?

CVE-2025-39925 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2025-39925?

Yes — CVE-2025-39925 has been patched. Fixed versions include 6.16.8 and 6.17. If you are running Linux kernel 5.4 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2025-39925 actively exploited?

No — CVE-2025-39925 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.