CVE-2023-52783

What it actually does

Null pointer dereference in wx_sw_init() when a wangxun device reports a custom subsystem vendor ID, because wx->mac_table allocation is skipped before the pointer is later dereferenced, resulting in kernel panic.

Why it matters to the business

Affected Linux systems may experience sudden kernel crashes and reboots during network device initialization, causing temporary loss of network connectivity and potential data loss for workloads running on those hosts.

How an attack unfolds

An attacker with local access supplies or emulates a wangxun device whose PCI configuration contains a custom subsystem vendor ID; during driver probe wx_sw_init() returns early without allocating mac_table, and subsequent code dereferences the null pointer, triggering a kernel panic.

How to fix it

Update the Linux kernel to a version containing commit 61a55071653974dab172d4c5d699bb365cfd13c9 or later; rebuild and reboot with the patched kernel; verify the fix is present by checking the commit in the running kernel source.

How to confirm the fix worked

Confirm the running kernel contains commit 61a55071653974dab172d4c5d699bb365cfd13c9; attempt device initialization with a custom subsystem vendor ID in a test environment and verify no panic occurs.

Typical attack path

1. Obtain local access or the ability to insert a PCI device with custom subsystem vendor ID
2. Trigger wangxun driver probe or device initialization
3. wx_sw_init() skips mac_table allocation due to vendor ID check
4. Later dereference of wx->mac_table causes null pointer panic

How to detect it

Search kernel logs for oops or panic messages referencing wx_sw_init, null pointer dereference, or wangxun driver; examine dmesg and syslog around device probe events for mac_table related faults.

• wx_sw_init
• mac_table
• wangxun
• null pointer dereference

What your security team should do

• Prioritize patching kernel packages on systems that use wangxun network devices
• Monitor vendor advisories for backported fixes in distribution kernels
• Restrict local device insertion privileges where feasible until patched