CVE-2026-97438 (GCVE-0-2026-97438)
Vulnerability from cvelistv5
Published
2026-09-24 16:03
Modified
2026-10-03 10:58
Severity ?
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: validate index entry key bounds [BUG] A malformed NTFS directory index entry can advertise a key_size larger than the bytes actually present in its NTFS_DE payload. Directory lookup then passes that malformed key to cmp_fnames(), which can read past the end of the kmalloc'ed index buffer. BUG: KASAN: slab-out-of-bounds in fname_full_size fs/ntfs3/ntfs.h:590 [inline] BUG: KASAN: slab-out-of-bounds in cmp_fnames+0x1ea/0x230 fs/ntfs3/index.c:46 Read of size 1 at addr ffff88801c313018 by task syz.6.3365/9279 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xd1/0x650 mm/kasan/report.c:482 kasan_report+0xfb/0x140 mm/kasan/report.c:595 __asan_report_load1_noabort+0x14/0x30 mm/kasan/report_generic.c:378 fname_full_size fs/ntfs3/ntfs.h:590 [inline] cmp_fnames+0x1ea/0x230 fs/ntfs3/index.c:46 hdr_find_e.isra.0+0x3ed/0x670 fs/ntfs3/index.c:762 indx_find+0x4b5/0x900 fs/ntfs3/index.c:1186 dir_search_u+0x2c0/0x460 fs/ntfs3/dir.c:254 ntfs_lookup+0x1cc/0x2a0 fs/ntfs3/namei.c:85 __lookup_slow+0x241/0x450 fs/namei.c:1816 lookup_slow fs/namei.c:1833 [inline] walk_component+0x31c/0x570 fs/namei.c:2151 link_path_walk+0x592/0xd60 fs/namei.c:2519 path_lookupat+0x138/0x660 fs/namei.c:2675 filename_lookup+0x1f3/0x560 fs/namei.c:2705 filename_setxattr+0xad/0x1c0 fs/xattr.c:660 path_setxattrat+0x1d8/0x280 fs/xattr.c:713 __do_sys_lsetxattr fs/xattr.c:754 [inline] __se_sys_lsetxattr fs/xattr.c:750 [inline] __x64_sys_lsetxattr+0xd0/0x150 fs/xattr.c:750 ... Allocated by task 9279: kasan_save_stack+0x39/0x70 mm/kasan/common.c:56 kasan_save_track+0x14/0x40 mm/kasan/common.c:77 kasan_save_alloc_info+0x37/0x60 mm/kasan/generic.c:573 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0xc3/0xd0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5650 [inline] __kmalloc_noprof+0x2bd/0x900 mm/slub.c:5662 kmalloc_noprof include/linux/slab.h:961 [inline] indx_read+0x41d/0xad0 fs/ntfs3/index.c:1059 indx_find+0x447/0x900 fs/ntfs3/index.c:1179 dir_search_u+0x2c0/0x460 fs/ntfs3/dir.c:254 ntfs_lookup+0x1cc/0x2a0 fs/ntfs3/namei.c:85 __lookup_slow+0x241/0x450 fs/namei.c:1816 lookup_slow fs/namei.c:1833 [inline] walk_component+0x31c/0x570 fs/namei.c:2151 link_path_walk+0x592/0xd60 fs/namei.c:2519 path_lookupat+0x138/0x660 fs/namei.c:2675 filename_lookup+0x1f3/0x560 fs/namei.c:2705 filename_setxattr+0xad/0x1c0 fs/xattr.c:660 path_setxattrat+0x1d8/0x280 fs/xattr.c:713 __do_sys_lsetxattr fs/xattr.c:754 [inline] __se_sys_lsetxattr fs/xattr.c:750 [inline] __x64_sys_lsetxattr+0xd0/0x150 fs/xattr.c:750 ... [CAUSE] The index-header validators only validated INDEX_HDR-level geometry. They did not walk each NTFS_DE to verify entry alignment, subnode layout, or that key_size fit inside the entry payload. They also allowed a last sentinel entry to carry a non-zero key_size. [FIX] Walk every NTFS_DE in ntfs3's index-header validators and reject entries with invalid layout, mismatched subnode state, oversized key_size, or non-zero sentinel keys before lookup or log replay can consume them.
References
Impacted products
Vendor Product Version
Linux Linux Version: 82cae269cfa953032fbb8980a7d554d60fb00b17
Version: 82cae269cfa953032fbb8980a7d554d60fb00b17
Version: 82cae269cfa953032fbb8980a7d554d60fb00b17
Version: 82cae269cfa953032fbb8980a7d554d60fb00b17
Version: 82cae269cfa953032fbb8980a7d554d60fb00b17
Version: 82cae269cfa953032fbb8980a7d554d60fb00b17
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs3/fslog.c",
            "fs/ntfs3/index.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c8d93bc4823baecab3c39b877e16ac5f8d4d41ba",
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "versionType": "git"
            },
            {
              "lessThan": "7feeb424bda7f6ffaf5090cdd01b300eaa74c02b",
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "versionType": "git"
            },
            {
              "lessThan": "d564a885219a655077eefafeb72395a4580ebd69",
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "versionType": "git"
            },
            {
              "lessThan": "a8f4fb6a7d58974ffc9aed597401528b181d76dc",
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "versionType": "git"
            },
            {
              "lessThan": "0257e3ea00e19129f3ad5c039d8b8fdff0796835",
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "versionType": "git"
            },
            {
              "lessThan": "98d6e5d9dc1d34dcffc61549617581a5fe1ef807",
              "status": "affected",
              "version": "82cae269cfa953032fbb8980a7d554d60fb00b17",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs3/fslog.c",
            "fs/ntfs3/index.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.222",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.189",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: validate index entry key bounds\n\n[BUG]\nA malformed NTFS directory index entry can advertise a key_size larger\nthan the bytes actually present in its NTFS_DE payload. Directory lookup\nthen passes that malformed key to cmp_fnames(), which can read past the\nend of the kmalloc\u0027ed index buffer.\n\nBUG: KASAN: slab-out-of-bounds in fname_full_size fs/ntfs3/ntfs.h:590 [inline]\nBUG: KASAN: slab-out-of-bounds in cmp_fnames+0x1ea/0x230 fs/ntfs3/index.c:46\nRead of size 1 at addr ffff88801c313018 by task syz.6.3365/9279\n\nCall Trace:\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xd1/0x650 mm/kasan/report.c:482\n kasan_report+0xfb/0x140 mm/kasan/report.c:595\n __asan_report_load1_noabort+0x14/0x30 mm/kasan/report_generic.c:378\n fname_full_size fs/ntfs3/ntfs.h:590 [inline]\n cmp_fnames+0x1ea/0x230 fs/ntfs3/index.c:46\n hdr_find_e.isra.0+0x3ed/0x670 fs/ntfs3/index.c:762\n indx_find+0x4b5/0x900 fs/ntfs3/index.c:1186\n dir_search_u+0x2c0/0x460 fs/ntfs3/dir.c:254\n ntfs_lookup+0x1cc/0x2a0 fs/ntfs3/namei.c:85\n __lookup_slow+0x241/0x450 fs/namei.c:1816\n lookup_slow fs/namei.c:1833 [inline]\n walk_component+0x31c/0x570 fs/namei.c:2151\n link_path_walk+0x592/0xd60 fs/namei.c:2519\n path_lookupat+0x138/0x660 fs/namei.c:2675\n filename_lookup+0x1f3/0x560 fs/namei.c:2705\n filename_setxattr+0xad/0x1c0 fs/xattr.c:660\n path_setxattrat+0x1d8/0x280 fs/xattr.c:713\n __do_sys_lsetxattr fs/xattr.c:754 [inline]\n __se_sys_lsetxattr fs/xattr.c:750 [inline]\n __x64_sys_lsetxattr+0xd0/0x150 fs/xattr.c:750\n ...\n\nAllocated by task 9279:\n kasan_save_stack+0x39/0x70 mm/kasan/common.c:56\n kasan_save_track+0x14/0x40 mm/kasan/common.c:77\n kasan_save_alloc_info+0x37/0x60 mm/kasan/generic.c:573\n poison_kmalloc_redzone mm/kasan/common.c:400 [inline]\n __kasan_kmalloc+0xc3/0xd0 mm/kasan/common.c:417\n kasan_kmalloc include/linux/kasan.h:262 [inline]\n __do_kmalloc_node mm/slub.c:5650 [inline]\n __kmalloc_noprof+0x2bd/0x900 mm/slub.c:5662\n kmalloc_noprof include/linux/slab.h:961 [inline]\n indx_read+0x41d/0xad0 fs/ntfs3/index.c:1059\n indx_find+0x447/0x900 fs/ntfs3/index.c:1179\n dir_search_u+0x2c0/0x460 fs/ntfs3/dir.c:254\n ntfs_lookup+0x1cc/0x2a0 fs/ntfs3/namei.c:85\n __lookup_slow+0x241/0x450 fs/namei.c:1816\n lookup_slow fs/namei.c:1833 [inline]\n walk_component+0x31c/0x570 fs/namei.c:2151\n link_path_walk+0x592/0xd60 fs/namei.c:2519\n path_lookupat+0x138/0x660 fs/namei.c:2675\n filename_lookup+0x1f3/0x560 fs/namei.c:2705\n filename_setxattr+0xad/0x1c0 fs/xattr.c:660\n path_setxattrat+0x1d8/0x280 fs/xattr.c:713\n __do_sys_lsetxattr fs/xattr.c:754 [inline]\n __se_sys_lsetxattr fs/xattr.c:750 [inline]\n __x64_sys_lsetxattr+0xd0/0x150 fs/xattr.c:750\n ...\n\n[CAUSE]\nThe index-header validators only validated INDEX_HDR-level geometry.\nThey did not walk each NTFS_DE to verify entry alignment, subnode\nlayout, or that key_size fit inside the entry payload. They also\nallowed a last sentinel entry to carry a non-zero key_size.\n\n[FIX]\nWalk every NTFS_DE in ntfs3\u0027s index-header validators and reject\nentries with invalid layout, mismatched subnode state, oversized\nkey_size, or non-zero sentinel keys before lookup or log replay can\nconsume them."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The oversized field is on-disk NTFS_DE.key_size in a directory INDEX_BUFFER. indx_read() kmallocs that buffer and the pre-fix index_hdr_check() accepted it; lsetxattr/open then reaches ntfs_lookup\u2192dir_search_u\u2192indx_find\u2192hdr_find_e\u2192cmp_fnames(), and ntfs_fill_super\u2192ntfs_extend_init\u2192dir_search_u hits the same walk. No SMB/NFS/TCP message carries key_size.\nAC:L - A crafted NTFS_DE with key_size larger than e-\u003esize minus sizeof(NTFS_DE), or a last sentinel with non-zero key_size, makes hdr_find_e() pass that length to cmp_fnames() on every lookup of that directory. Pre-fix index_hdr_check() only tested INDEX_HDR de_off/used/total. No race.\nPR:N - Crafting the image needs no host account. ntfs_fs_type.fs_flags is only FS_REQUIRES_DEV|FS_ALLOW_IDMAP (no FS_USERNS_MOUNT), so mount_capable() requires init-namespace CAP_SYS_ADMIN; that privileged mount of the attacker image is scored as UI:R, not attacker privilege.\nUI:R - index_hdr_check() and hdr_find_e() run only after path_mount\u2192get_tree_bdev\u2192ntfs_fill_super attaches the attacker-supplied block device. Because ntfs3 is not FS_USERNS_MOUNT, a victim, automounter, or admin must mount that image; ntfs_extend_init() even calls dir_search_u() during fill_super.\nS:U - The slab over-read in fname_full_size()/cmp_fnames() and any oops stay in the host kernel that mounted the volume. This is not a KVM/Xen guest-to-host escape or an IOMMU/DMA bypass.\nC:H - hdr_find_e() calls cmp_fnames(key, 0, e+1, key_size). fname_full_size() then ntfs_cmp_names_cpu() walk ATTR_FILE_NAME.name_len (u8, up to 255 UTF-16 units, 510 bytes) past a truncated NTFS_DE at the tail of indx_read()\u0027s kmalloc(1\u003c\u003cindex_bits) object; that is not a few-byte leak.\nI:N - cmp_fnames() only returns a comparison integer used to pick an index slot. hdr_insert_de() and fslog memmove using e-\u003esize or dlen, not the inflated key_size, so this is not an out-of-bounds write or control-flow hijack.\nA:H - KASAN reported a slab-out-of-bounds load of size 1 in fname_full_size() from indx_read()\u0027s kmalloc INDEX_BUFFER (typically 4K). An entry at the buffer tail with oversized key_size reads into the next page and can oops the kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-03T10:58:23.213Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c8d93bc4823baecab3c39b877e16ac5f8d4d41ba"
        },
        {
          "url": "https://git.kernel.org/stable/c/7feeb424bda7f6ffaf5090cdd01b300eaa74c02b"
        },
        {
          "url": "https://git.kernel.org/stable/c/d564a885219a655077eefafeb72395a4580ebd69"
        },
        {
          "url": "https://git.kernel.org/stable/c/a8f4fb6a7d58974ffc9aed597401528b181d76dc"
        },
        {
          "url": "https://git.kernel.org/stable/c/0257e3ea00e19129f3ad5c039d8b8fdff0796835"
        },
        {
          "url": "https://git.kernel.org/stable/c/98d6e5d9dc1d34dcffc61549617581a5fe1ef807"
        }
      ],
      "title": "fs/ntfs3: validate index entry key bounds",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97438",
    "datePublished": "2026-09-24T16:03:51.466Z",
    "dateReserved": "2026-09-24T14:53:16.869Z",
    "dateUpdated": "2026-10-03T10:58:23.213Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.