CVE-2026-13215 Zephyr ext2 mount: unvalidated superblock block size causes out-of-bounds write from a crafted filesystem image

The Zephyr ext2 filesystem driver fails to validate the slogblocksize field of the on-disk superblock when mounting a filesystem. ext2verifydisksuperblock in subsys/fs/ext2/ext2impl.c checks the magic number, revision, inode size and group counts, but never bounds slogblocksize. On a successful...