CVE-2026-53130: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START omfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE), but it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440). Later, omfs_make_empty() uses sbi->s_sys_blocksize - OMFS_DIR_START as the length argument to memset(). Since s_sys_blocksize is u32, a crafted filesystem image with s_sys_blocksize < OMFS_DIR_START causes an unsigned underflow there, wrapping to a value near 2^32. That drives a ~4 GiB memset() from bh->b_data + OMFS_DIR_START and overwrites kernel memory far beyond the backing block buffer. Add the corresponding lower-bound check alongside the existing upper-bound check in omfs_fill_super(), so that malformed images are rejected during superblock validation before any filesystem data is processed.

Affected products

• Linux Linux Kernel: from 2.6.27, before 5.10.258 (fixed in 5.10.258); from 5.11, before 5.15.209 (fixed in 5.15.209); from 5.16, before 6.1.175 (fixed in 6.1.175); from 6.2, before 6.6.141 (fixed in 6.6.141); from 6.7, before 6.12.91 (fixed in 6.12.91); from 6.13, before 6.18.33 (fixed in 6.18.33); …

Published 2026-06-24. Last modified 2026-07-06.