fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START_CVE-2026-53130

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START\n\nomfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE),\nbut it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440).\n\nLater, omfs_make_empty() uses\n\n    sbi->s_sys_blocksize - OMFS_DIR_START\n\nas the length argument to memset().  Since s_sys_blocksize is u32,\na crafted filesystem image with s_sys_blocksize < OMFS_DIR_START causes\nan unsigned underflow there, wrapping to a value near 2^32.  That drives\na ~4 GiB memset() from bh->b_data + OMFS_DIR_START and overwrites kernel\nmemory far beyond the backing block buffer.\n\nAdd the corresponding lower-bound check alongside the existing upper-bound\ncheck in omfs_fill_super(), so that malformed images are rejected during\nsuperblock validation before any filesystem data is processed.",
    "published": "2026-06-24T16:30:57.227Z",
    "modified": "2026-06-28T06:39:22.273Z",
    "type": "cve",
    "title": "fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/fbc72f5c645155dc2ed3573243ed20f9913e3a54\nhttps://git.kernel.org/stable/c/5822a05a841a10794ad818620dd2af490b0705d3\nhttps://git.kernel.org/stable/c/754ff1bea3819a90c6f33cccfc1a299ef7609f07\nhttps://git.kernel.org/stable/c/131ea3e57fc22936ed0e2c8330f2e36106172f51\nhttps://git.kernel.org/stable/c/79f84af38c9fef9deb0e02c79eb969b5541c2644\nhttps://git.kernel.org/stable/c/6561afc38398e3518a29c5eebb975c30468f98a6\nhttps://git.kernel.org/stable/c/817f16ed62bc58a168417bfb5e859c2a370bab03\nhttps://git.kernel.org/stable/c/0621c385fda1376e967f37ccd534c26c3e511d14",
    "id": "CVE-2026-53130",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux a3ab7155ea21aadc8a4d5687e91b3d876973185e\nLinux Linux 2.6.27",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "a3ab7155ea21aadc8a4d5687e91b3d876973185e",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}