The vulnerability lies in the Zephyr ext2 filesystem driver, where the on‑disk block bitmap is validated without bounding the number of bits by the allocated bitmap size. A specially crafted ext2 image with an excessively large s_blocks_count causes the driver to read across 512 MB of memory beyond the intended bitmap block, leading to a kernel fault. The read is not exploitable for data disclosure; instead it results in a denial of service by crashing the system when the flawed image is mounted.

This issue affects the Zephyr project Zephyr kernel; specific product and version numbers are not listed in the advisory, so any build that includes the vulnerable ext2 filesystem driver is potentially impacted.

The CVSS score of 5.5 indicates medium severity. No EPSS score is reported, so the publicly estimated exploitation probability is unknown and presumably low. The vulnerability is not listed in the CISA KEV catalog. The attack vector is mounting a malicious ext2 image from removable media, a disk/flash partition, or a downloaded file, which triggers the kernel‑privileged mount operation and can crash the device if the image contains an oversized s_blocks_count.