CVE-2025-39796

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: lapbether: ignore ops-locked netdevs

Syzkaller managed to trigger lock dependency in xsk_notify via

register_netdevice. As discussed in [0], using register_netdevice

in the notifiers is problematic so skip adding lapbeth for ops-locked

devices.

xsk_notifier+0xa4/0x280 net/xdp/xsk.c:1645

notifier_call_chain+0xbc/0x410 kernel/notifier.c:85

call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230

call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]

call_netdevice_notifiers net/core/dev.c:2282 [inline]

unregister_netdevice_many_notify+0xf9d/0x2700 net/core/dev.c:12077

unregister_netdevice_many net/core/dev.c:12140 [inline]

unregister_netdevice_queue+0x305/0x3f0 net/core/dev.c:11984

register_netdevice+0x18f1/0x2270 net/core/dev.c:11149

lapbeth_new_device drivers/net/wan/lapbether.c:420 [inline]

lapbeth_device_event+0x5b1/0xbe0 d

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References