Linux Kernel Vulnerability in Bidirectional Socket-Node Lookups

CVE-2023-53496

What is CVE-2023-53496?

A vulnerability exists in the Linux kernel related to the bidirectional lookup between sockets and NUMA nodes. The issue arises when the number of CPUs configured is smaller than the actual CPUs present. This configuration leads to incomplete mapping information, resulting in improper socket-node tables. When these tables are accessed, it can lead to system errors, as the system may attempt to reference disabled CPUs. The vulnerability highlights the need for a revised methodology in socket-node lookups, urging a shift from using CPU references to directly using APICIDs associated with valid NUMA nodes to prevent system instability.

References