fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START (Linux Linux)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.19 % · percentile 8 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Analyzed
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.
Weaknesses (CWE)
- CWE-191 — Integer Underflow (Wrap or Wraparound)
References
- https://git.kernel.org/stable/c/fbc72f5c645155dc2ed3573243ed20f9913e3a54
- https://git.kernel.org/stable/c/5822a05a841a10794ad818620dd2af490b0705d3
- https://git.kernel.org/stable/c/754ff1bea3819a90c6f33cccfc1a299ef7609f07
- https://git.kernel.org/stable/c/131ea3e57fc22936ed0e2c8330f2e36106172f51
- https://git.kernel.org/stable/c/79f84af38c9fef9deb0e02c79eb969b5541c2644
- https://git.kernel.org/stable/c/6561afc38398e3518a29c5eebb975c30468f98a6
- https://git.kernel.org/stable/c/817f16ed62bc58a168417bfb5e859c2a370bab03
- https://git.kernel.org/stable/c/0621c385fda1376e967f37ccd534c26c3e511d14
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | Linux |
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | NVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary) |
European references
- ENISA EUVD · EUVD-2026-38998
- GCVE · GCVE-0-2026-53130
CERT-FR advisories
- CERTFR-2026-AVI-1252 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1229 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1162 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1093 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1066 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0985 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0954 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0926 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0862 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 2.6.27 < 5.10.258cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.11 < 5.15.209cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.16 < 6.1.175cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.2 < 6.6.141cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.7 < 6.12.91cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.13 < 6.18.33cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.19 < 7.0.10
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected a3ab7155ea21aadc8a4d5687e91b3d876973185e < fbc72f5c645155dc2ed3573243ed20f9913e3a54 ; affected a3ab7155ea21aadc8a4d5687e91b3d876973185e < 5822a05a841a10794ad818620dd2af490b0705d3 ; affected a3ab7155ea21aadc8a4d5687e91b3d876973185e < 754ff1bea3819a90c6f33cccfc1a299ef7609f07 ; affected a3ab7155ea21aadc8a4d5687e91b3d876973185e < 131ea3e57fc22936ed0e2c8330f2e36106172f51 ; affected a3ab7155ea21aadc8a4d5687e91b3d876973185e < 79f84af38c9fef9deb0e02c79eb969b5541c2644 ; affected a3ab7155ea21aadc8a4d5687e91b3d876973185e < 6561afc38398e3518a29c5eebb975c30468f98a6 |
| Linux · Linux | affected 2.6.27 ; unaffected 0 < 2.6.27 ; unaffected 5.10.258 ≤ 5.10.* ; unaffected 5.15.209 ≤ 5.15.* ; unaffected 6.1.175 ≤ 6.1.* ; unaffected 6.6.141 ≤ 6.6.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |