CVE-2026-53130

Description

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.

CVSS breakdown

Affected products

• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – fbc72f5c645155dc2ed3573243ed20f9913e3a54
• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – 5822a05a841a10794ad818620dd2af490b0705d3
• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – 754ff1bea3819a90c6f33cccfc1a299ef7609f07
• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – 131ea3e57fc22936ed0e2c8330f2e36106172f51
• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – 79f84af38c9fef9deb0e02c79eb969b5541c2644
• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – 6561afc38398e3518a29c5eebb975c30468f98a6
• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – 817f16ed62bc58a168417bfb5e859c2a370bab03
• Linux / Linuxa3ab7155ea21aadc8a4d5687e91b3d876973185e – 0621c385fda1376e967f37ccd534c26c3e511d14
• Linux / Linux2.6.27 – 2.6.27
• Linux / Linux0 – 2.6.27
• Linux / Linux5.10.258 – 5.10.*
• Linux / Linux5.15.209 – 5.15.*
• Linux / Linux6.1.175 – 6.1.*
• Linux / Linux6.6.141 – 6.6.*
• Linux / Linux6.12.91 – 6.12.*
• Linux / Linux6.18.33 – 6.18.*
• Linux / Linux7.0.10 – 7.0.*
• Linux / Linux7.1 – *

References

• MISChttps://git.kernel.org/stable/c/fbc72f5c645155dc2ed3573243ed20f9913e3a54
• MISChttps://git.kernel.org/stable/c/5822a05a841a10794ad818620dd2af490b0705d3
• MISChttps://git.kernel.org/stable/c/754ff1bea3819a90c6f33cccfc1a299ef7609f07
• MISChttps://git.kernel.org/stable/c/131ea3e57fc22936ed0e2c8330f2e36106172f51
• MISChttps://git.kernel.org/stable/c/79f84af38c9fef9deb0e02c79eb969b5541c2644
• MISChttps://git.kernel.org/stable/c/6561afc38398e3518a29c5eebb975c30468f98a6
• MISChttps://git.kernel.org/stable/c/817f16ed62bc58a168417bfb5e859c2a370bab03
• MISChttps://git.kernel.org/stable/c/0621c385fda1376e967f37ccd534c26c3e511d14