CVE-2023-53254

In the Linux kernel, the following vulnerability has been resolved:

cacheinfo: Fix shared_cpu_map to handle shared caches at different levels

The cacheinfo sets up the shared_cpu_map by checking whether the caches with the same index are shared between CPUs. However, this will trigger slab-out-of-bounds access if the CPUs do not have the same cache hierarchy. Another problem is the mismatched shared_cpu_map when the shared cache does not have the same index between CPUs.

CPU0 I D L3 index 0 1 2 x ^ ^ ^ ^ index 0 1 2 3 CPU1 I D L2 L3

This patch checks each cache is shared with all caches on other CPUs.

This vulnerability is rated as Moderate impact for Red Hat Enterprise Linux because exploitation requires local access and relies on hardware platforms with asymmetric CPU cache hierarchies, restricting the primary risk to local denial of service. The underlying flaw resides in the kernel cache topology enumeration logic executed during processor detection. Because typical enterprise deployments utilize uniform cache layouts across symmetric CPU cores, exposure is minimal under standard production configurations.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.