CVE-2025-39925

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 v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/7fcbe5b2c6a4b5407bf2241fdb71e0a390f6ab9a	Patch
https://git.kernel.org/stable/c/da9e8f429139928570407e8f90559b5d46c20262	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:6.17:rc1::::::
	cpe:2.3:o:linux:linux_kernel:6.17:rc2::::::
	cpe:2.3:o:linux:linux_kernel:6.17:rc3::::::
	cpe:2.3:o:linux:linux_kernel:6.17:rc4::::::
	cpe:2.3:o:linux:linux_kernel:6.17:rc5::::::

History

No history.

Information

Published : 2025-10-01 08:15

Updated : 2026-01-14 18:16

NVD link : CVE-2025-39925

Mitre link : CVE-2025-39925

CVE.ORG link : CVE-2025-39925

JSON object : View

Products Affected

linux

linux_kernel

CWE

NVD-CWE-noinfo

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