fs/ntfs3: validate rec->used in journal-replay file record check_CVE-2026-31716

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: validate rec->used in journal-replay file record check\n\ncheck_file_record() validates rec->total against the record size but\nnever validates rec->used.  The do_action() journal-replay handlers read\nrec->used from disk and use it to compute memmove lengths:\n\n  DeleteAttribute:    memmove(attr, ..., used - asize - roff)\n  CreateAttribute:    memmove(..., attr, used - roff)\n  change_attr_size:   memmove(..., used - PtrOffset(rec, next))\n\nWhen rec->used is smaller than the offset of a validated attribute, or\nlarger than the record size, these subtractions can underflow allowing\nus to copy huge amounts of memory in to a 4kb buffer, generally\nconsidered a bad idea overall.\n\nThis requires a corrupted filesystem, which isn't a threat model the\nkernel really needs to worry about, but checking for such an obvious\nout-of-bounds value is good to keep things robust, especially on journal\nreplay\n\nFix this up by bounding rec->used correctly.\n\nThis is much like commit b2bc7c44ed17 (\"fs/ntfs3: Fix slab-out-of-bounds\nread in DeleteIndexEntryRoot\") which checked different values in this\nsame switch statement.",
    "published": "2026-05-01T13:56:11.263Z",
    "modified": "2026-05-03T05:45:36.603Z",
    "type": "cve",
    "title": "fs/ntfs3: validate rec->used in journal-replay file record check",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/f90b8a1798b750755a9e9aee66678f0a1820bbaf\nhttps://git.kernel.org/stable/c/4b1613d7e2deda831a97e427d1ea586e50fe1be5\nhttps://git.kernel.org/stable/c/0112e6279420d4005b3d57af36fb45c01b8d0116\nhttps://git.kernel.org/stable/c/f79d0403ea20a81bc29105bba54fbcab54e8c403\nhttps://git.kernel.org/stable/c/0ca0485e4b2e837ebb6cbd4f2451aba665a03e4b",
    "id": "CVE-2026-31716",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux b46acd6a6a627d876898e1c84d3f84902264b445\nLinux Linux b46acd6a6a627d876898e1c84d3f84902264b445\nLinux Linux b46acd6a6a627d876898e1c84d3f84902264b445\nLinux Linux b46acd6a6a627d876898e1c84d3f84902264b445\nLinux Linux b46acd6a6a627d876898e1c84d3f84902264b445\nLinux Linux 5.15",
    "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": {
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        "baseScore": 0,
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        "privilegesRequired": "",
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        "confidentialityImpact": "",
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        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
    "vendor": "Linux",
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    "ai_score": 0
}