CVE-2026-46142 Linux CVE debrief

Who should care

Organizations running Linux-based virtualization infrastructure with SR-IOV-enabled network adapters, particularly cloud providers and enterprises with high-density virtualized workloads. System administrators managing KVM, Xen, or other hypervisor environments using libwx-compatible network hardware should prioritize this patch.

Technical summary

The libwx network driver in the Linux kernel contained a vulnerability where Virtual Functions (VFs) would attempt to read the WX_CFG_PORT_ST register during initialization. This register is restricted to Physical Functions (PFs) only. When a VF performed this illegal access, it triggered a system hang. The vulnerability affects SR-IOV deployments where network interface cards are virtualized into multiple VFs. The resolution modifies the driver to obtain the bus function ID directly from PCI_FUNC(pdev->devfn) when operating as a VF, bypassing the need to access the restricted register.

Defensive priority

high

Recommended defensive actions

• Apply the relevant kernel patch from the stable kernel tree to prevent VF initialization from causing system hangs
• Verify that Virtual Functions on affected systems are properly isolated from PF-restricted registers
• Review SR-IOV configurations to ensure VF drivers are running patched versions
• Monitor system logs for illegal register access warnings that may indicate exploitation attempts
• Prioritize patching on multi-tenant or virtualization-heavy environments where SR-IOV is actively used

Evidence notes

The vulnerability description indicates this was resolved in the Linux kernel. Multiple stable kernel commits are referenced, suggesting backports to affected versions. The issue is specific to SR-IOV (Single Root I/O Virtualization) environments where VFs are initialized.

Official resources