CVE-2026-55392 NILFS utilities - Undefined Behavior and Out-of-Memory via Unvalidated s_log_block_size

NILFS utilities through 2.3.0, fixed in commit 26efb5d, nilfssbisvalid function fails to validate slogblocksize field in NILFS2 superblock before bit-shift operations. Attackers supplying crafted NILFS2 images trigger undefined behavior through oversized shifts or out-of-memory conditions, crashi...