Executive brief
A vulnerability in the Linux kernel's Wangxun (libwx) Ethernet driver can cause a complete system hang. This occurs when the system attempts to initialize a Virtual Function (VF) network interface and incorrectly tries to access a restricted hardware register. An exploit or accidental trigger of this flaw would result in a denial-of-service, requiring a physical reboot to restore operations.
Technical details
A vulnerability exists in the Wangxun Ethernet library (libwx) within the Linux kernel's networking subsystem. The root cause is an illegal register access in `wx_sw_init` where the driver attempts to read the `WX_CFG_PORT_ST` register to determine the LAN ID. This register is restricted to Physical Functions (PF); when accessed by a Virtual Function (VF) during initialization, it triggers a hardware-level error that results in a system hang. The fix introduces a check for `pdev->is_virtfn` to obtain the function ID directly from the PCI configuration instead of the restricted register. This issue affects systems utilizing Wangxun Ethernet controllers in virtualized environments.
Affected products
- Linux Linux Kernel libwx driver
Timeline
- 2026-04-29: patched: Initial patch submitted by Jiawen Wu
- 2026-05-28: disclosed: CVE published to NVD
References
- https://git.kernel.org/stable/c/33c5bb50b9c40e8451e6aec4487a31d794b98d92
- https://git.kernel.org/stable/c/68a007a701bc06fa426507c551ef12514f2e721d
- https://git.kernel.org/stable/c/694de316f607fe2473d52ca0707e3918e72c1562
- https://git.kernel.org/stable/c/d3bd8040497968f6f5470018724ef7b0df92f707
- https://git.kernel.org/stable/c/f6e656f7cea16b638675a2ab7d7e4cf2516c5eb0