GHSA-7V7P-59M6-6H9X
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: bound copy_lcns dp->page_lcns[] index in analysis pass
In log_replay()'s analysis pass, after find_dp() returns a valid DIR_PAGE_ENTRY for the (target_attr, target_vcn) tuple, the copy_lcns block walks lrh->lcns_follow further entries:
t16 = le16_to_cpu(lrh->lcns_follow);
for (i = 0; i < t16; i++) {
size_t j = (size_t)(le64_to_cpu(lrh->target_vcn) -
le64_to_cpu(dp->vcn));
dp->page_lcns[j + i] = lrh->page_lcns[i];
}
find_dp() only validates that target_vcn falls within [dp->vcn, dp->vcn + dp->lcns_follow), i.e., that the FIRST cluster is covered. The walk through the further entries is not bounded against dp->lcns_follow. For a malformed LRH where target_vcn = dp->vcn + dp->lcns_follow - 1 and lrh->lcns_follow > 1, the i > 0 writes overflow the dp's allocated page_lcns[] array.
Add the missing j + lrh->lcns_follow <= dp->lcns_follow guard.
Reproduced under UML+KASAN on mainline 8d90b09e6741 as a slab-out-of-bounds write of size 8 from log_replay+0x68d4 on the mount path.
This is distinct from Pavitra Jha's 2026-05-02 patch ("fs/ntfs3: validate lcns_follow in log_replay conversion", 20260502154252.164586-1-jhapavitra98@gmail.com) which addresses the separate version-0 dirty-page-table conversion path's memmove(&dp->vcn, ...) call. The two fixes are complementary; both should land.
[almaz.alexandrovich@paragon-software.com: clang-formatted the changes, fixed conflicts]
{
"affected": [],
"aliases": [
"CVE-2026-72196"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:21:38Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: bound copy_lcns dp-\u003epage_lcns[] index in analysis pass\n\nIn log_replay()\u0027s analysis pass, after find_dp() returns a\nvalid DIR_PAGE_ENTRY for the (target_attr, target_vcn) tuple,\nthe copy_lcns block walks lrh-\u003elcns_follow further entries:\n\n\tt16 = le16_to_cpu(lrh-\u003elcns_follow);\n\tfor (i = 0; i \u003c t16; i++) {\n\t size_t j = (size_t)(le64_to_cpu(lrh-\u003etarget_vcn) -\n\t le64_to_cpu(dp-\u003evcn));\n\t dp-\u003epage_lcns[j + i] = lrh-\u003epage_lcns[i];\n\t}\n\nfind_dp() only validates that target_vcn falls within\n[dp-\u003evcn, dp-\u003evcn + dp-\u003elcns_follow), i.e., that the FIRST\ncluster is covered. The walk through the further entries is\nnot bounded against dp-\u003elcns_follow. For a malformed LRH\nwhere target_vcn = dp-\u003evcn + dp-\u003elcns_follow - 1 and\nlrh-\u003elcns_follow \u003e 1, the i \u003e 0 writes overflow the dp\u0027s\nallocated page_lcns[] array.\n\nAdd the missing j + lrh-\u003elcns_follow \u003c= dp-\u003elcns_follow guard.\n\nReproduced under UML+KASAN on mainline 8d90b09e6741 as a\nslab-out-of-bounds write of size 8 from log_replay+0x68d4 on\nthe mount path.\n\nThis is distinct from Pavitra Jha\u0027s 2026-05-02 patch\n(\"fs/ntfs3: validate lcns_follow in log_replay conversion\",\n\u003c20260502154252.164586-1-jhapavitra98@gmail.com\u003e) which\naddresses the separate version-0 dirty-page-table conversion\npath\u0027s memmove(\u0026dp-\u003evcn, ...) call. The two fixes are\ncomplementary; both should land.\n\n[almaz.alexandrovich@paragon-software.com: clang-formatted the changes,\nfixed conflicts]",
"id": "GHSA-7v7p-59m6-6h9x",
"modified": "2026-08-17T06:33:15Z",
"published": "2026-08-15T06:32:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72196"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0f13e823bf86bd1800168ea0bb5bca8b8500a81c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/49c86dae0c0ccb8d98ddcdc46987259389c816dd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5e7b598660cfa8e5af172cf4c65cffc126333307"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9b3d8cc9d54fcded4de51b2b1026ae7182512077"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9b7c28d8c61bdb041936222a09a708531a1c2921"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d240cd98f5f7b65c90f6b2b6abe3232ccdc405ab"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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