The Linux kernel mchp23k256 driver stored chip capacity information in both the device tree (OF) match table and the SPI id table. The probe function used of_device_get_match_data(), which caused a fallback to default chip capacity data even when the SPI id table selected a different chip. This could lead to incorrect memory geometry being used for SPI devices matched only by the id table. The vulnerability was resolved by changing the probe to use spi_get_device_match_data() to consume SPI id-table driver_data when OF match data is absent, maintaining the existing default fallback while avoiding incorrect MTD geometry for id-table-only matches.

Incorrect chip capacity information could cause the driver to misinterpret the memory geometry of SPI devices matched only by the SPI id table. This may lead to improper operation of the memory technology device (MTD), potentially causing data corruption or device malfunction. However, no known exploits are reported in the wild.

A fix has been implemented in the Linux kernel to correct the probe logic in the mchp23k256 driver. Users should update to a kernel version that includes this fix. Since this is a kernel driver vulnerability, applying the official kernel update is the recommended remediation. Patch status is not explicitly confirmed in the provided data; users should verify with the Linux kernel vendor advisory for the exact fixed version.