Linux Kernel CVE-2026-43212

The vulnerability resides in the LoongArch architecture-specific implementation of cpumask_of_node(), a kernel function that returns the CPU affinity mask for a given NUMA node. NUMA_NO_NODE is a special sentinel value (typically -1) used throughout the kernel to indicate 'no specific NUMA node' or fallback to default node selection. The LoongArch implementation failed to validate this edge case, potentially causing out-of-bounds memory access when the invalid node index is used to look up CPU masks in node-to-CPU mapping tables. This affects systems running LoongArch processors with NUMA topology support. The affected CPE strings indicate broad historical exposure dating back to kernel commit 1da177e4c3f4 (the initial Linux 2.6.12 release in 2005), though LoongArch architecture support was only added much later, so practical exposure is limited to kernels with LoongArch support. While no CWE is assigned, this represents improper input validation (CWE-20) leading to potential out-of-bounds read (CWE-125).