FKIE_CVE-2026-72353

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:18
Severity
8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ntfs: avoid stale runlist element dereference in fallocate ntfs_attr_fallocate() allocates holes and delayed allocations inside initialized size by looking up the current runlist element under ni->runlist.lock. The returned struct runlist_element is only a borrowed pointer into ni->runlist.rl. A writer can replace and free that array after the read lock is dropped, so later reads of rl->lcn, rl->length and rl->vcn can touch freed memory. The buggy scenario involves two paths, with each column showing the order within that path: ntfs_attr_fallocate(): 1. Take ni->runlist.lock for read. 2. Get rl from ntfs_attr_find_vcn_nolock(). 3. Drop ni->runlist.lock. 4. Read rl->lcn, rl->length and rl->vcn. mmap page_mkwrite: 1. Enter ntfs_filemap_page_mkwrite(). 2. Reach __ntfs_write_iomap_begin() and ntfs_attr_map_cluster(). 3. Merge allocation state with ntfs_runlists_merge(). 4. Reallocate ni->runlist.rl in ntfs_rl_realloc(), freeing the old array. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in ntfs_attr_fallocate+0xbb8/0xd00 Call Trace: <TASK> dump_stack_lvl+0x66/0xa0 print_report+0xce/0x630 ? ntfs_attr_fallocate+0xbb8/0xd00 ? srso_alias_return_thunk+0x5/0xfbef5 ? __virt_addr_valid+0x20d/0x410 ? ntfs_attr_fallocate+0xbb8/0xd00 kasan_report+0xe0/0x110 ? ntfs_attr_fallocate+0xbb8/0xd00 ntfs_attr_fallocate+0xbb8/0xd00 ? lock_acquire+0x2b8/0x2f0 ? __pfx_ntfs_attr_fallocate+0x10/0x10 ? 0xffffffffc0000095 ? down_write+0x10d/0x1e0 ntfs_fallocate+0x5c9/0x1d00 ? __pfx_ntfs_fallocate+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_acquire+0x2b8/0x2f0 ? srso_alias_return_thunk+0x5/0xfbef5 ? selinux_file_permission+0x3a7/0x510 vfs_fallocate+0x29d/0xd30 __x64_sys_fallocate+0xc7/0x150 ? do_syscall_64+0x81/0x6a0 do_syscall_64+0x115/0x6a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Allocated by task 410: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 __kvmalloc_node_noprof+0x353/0x920 ntfs_rl_realloc+0x3f/0x110 ntfs_runlists_merge+0xaa3/0x3010 ntfs_attr_map_cluster+0x4e5/0xf80 ntfs_attr_fallocate+0x53f/0xd00 ntfs_fallocate+0x5c9/0x1d00 vfs_fallocate+0x29d/0xd30 __x64_sys_fallocate+0xc7/0x150 do_syscall_64+0x115/0x6a0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 424: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x5f/0x80 kfree+0x307/0x580 ntfs_rl_realloc+0x6f/0x110 ntfs_runlists_merge+0x7b1/0x3010 ntfs_attr_map_cluster+0x4e5/0xf80 __ntfs_write_iomap_begin+0x8cd/0x2280 iomap_iter+0x6de/0x11e0 iomap_page_mkwrite+0x391/0x650 ntfs_filemap_page_mkwrite+0x1ac/0x400 do_page_mkwrite+0x15c/0x280 __handle_mm_fault+0xd6d/0x1ca0 handle_mm_fault+0x19c/0x470 do_user_addr_fault+0x23b/0x9c0 exc_page_fault+0x5c/0xc0 asm_exc_page_fault+0x26/0x30 Fix this by copying the needed runlist fields while the read lock is still held and using only those scalar snapshots after unlocking. After the snapshot, ntfs_attr_map_cluster() can also find that the range is already mapped and return balloc=false. Only call ntfs_dio_zero_range() when new clusters were allocated, matching the write iomap path and preserving the zero-newly-allocated-holes behavior.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3dd3e43f17cda174009a51fe668046ed7afef46a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/88496c4ac5a6ade75619f4b1015706a8b924d50a
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs/attrib.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3dd3e43f17cda174009a51fe668046ed7afef46a",
              "status": "affected",
              "version": "495e90fa334828d4119061e2726af51d0a0fb4ed",
              "versionType": "git"
            },
            {
              "lessThan": "88496c4ac5a6ade75619f4b1015706a8b924d50a",
              "status": "affected",
              "version": "495e90fa334828d4119061e2726af51d0a0fb4ed",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs/attrib.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: avoid stale runlist element dereference in fallocate\n\nntfs_attr_fallocate() allocates holes and delayed allocations inside\ninitialized size by looking up the current runlist element under\nni-\u003erunlist.lock. The returned struct runlist_element is only a borrowed\npointer into ni-\u003erunlist.rl. A writer can replace and free that array\nafter the read lock is dropped, so later reads of rl-\u003elcn, rl-\u003elength and\nrl-\u003evcn can touch freed memory.\n\nThe buggy scenario involves two paths, with each column showing the order\nwithin that path:\n\nntfs_attr_fallocate():\n  1. Take ni-\u003erunlist.lock for read.\n  2. Get rl from ntfs_attr_find_vcn_nolock().\n  3. Drop ni-\u003erunlist.lock.\n  4. Read rl-\u003elcn, rl-\u003elength and rl-\u003evcn.\n\nmmap page_mkwrite:\n  1. Enter ntfs_filemap_page_mkwrite().\n  2. Reach __ntfs_write_iomap_begin() and ntfs_attr_map_cluster().\n  3. Merge allocation state with ntfs_runlists_merge().\n  4. Reallocate ni-\u003erunlist.rl in ntfs_rl_realloc(), freeing the old array.\n\nValidation reproduced this kernel report:\nBUG: KASAN: slab-use-after-free in ntfs_attr_fallocate+0xbb8/0xd00\n\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x66/0xa0\n print_report+0xce/0x630\n ? ntfs_attr_fallocate+0xbb8/0xd00\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? __virt_addr_valid+0x20d/0x410\n ? ntfs_attr_fallocate+0xbb8/0xd00\n kasan_report+0xe0/0x110\n ? ntfs_attr_fallocate+0xbb8/0xd00\n ntfs_attr_fallocate+0xbb8/0xd00\n ? lock_acquire+0x2b8/0x2f0\n ? __pfx_ntfs_attr_fallocate+0x10/0x10\n ? 0xffffffffc0000095\n ? down_write+0x10d/0x1e0\n ntfs_fallocate+0x5c9/0x1d00\n ? __pfx_ntfs_fallocate+0x10/0x10\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? lock_acquire+0x2b8/0x2f0\n ? srso_alias_return_thunk+0x5/0xfbef5\n ? selinux_file_permission+0x3a7/0x510\n vfs_fallocate+0x29d/0xd30\n __x64_sys_fallocate+0xc7/0x150\n ? do_syscall_64+0x81/0x6a0\n do_syscall_64+0x115/0x6a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nAllocated by task 410:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x14/0x30\n __kasan_kmalloc+0xaa/0xb0\n __kvmalloc_node_noprof+0x353/0x920\n ntfs_rl_realloc+0x3f/0x110\n ntfs_runlists_merge+0xaa3/0x3010\n ntfs_attr_map_cluster+0x4e5/0xf80\n ntfs_attr_fallocate+0x53f/0xd00\n ntfs_fallocate+0x5c9/0x1d00\n vfs_fallocate+0x29d/0xd30\n __x64_sys_fallocate+0xc7/0x150\n do_syscall_64+0x115/0x6a0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nFreed by task 424:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x14/0x30\n kasan_save_free_info+0x3b/0x60\n __kasan_slab_free+0x5f/0x80\n kfree+0x307/0x580\n ntfs_rl_realloc+0x6f/0x110\n ntfs_runlists_merge+0x7b1/0x3010\n ntfs_attr_map_cluster+0x4e5/0xf80\n __ntfs_write_iomap_begin+0x8cd/0x2280\n iomap_iter+0x6de/0x11e0\n iomap_page_mkwrite+0x391/0x650\n ntfs_filemap_page_mkwrite+0x1ac/0x400\n do_page_mkwrite+0x15c/0x280\n __handle_mm_fault+0xd6d/0x1ca0\n handle_mm_fault+0x19c/0x470\n do_user_addr_fault+0x23b/0x9c0\n exc_page_fault+0x5c/0xc0\n asm_exc_page_fault+0x26/0x30\n\nFix this by copying the needed runlist fields while the read lock is still\nheld and using only those scalar snapshots after unlocking.\n\nAfter the snapshot, ntfs_attr_map_cluster() can also find that the range\nis already mapped and return balloc=false. Only call ntfs_dio_zero_range()\nwhen new clusters were allocated, matching the write iomap path and\npreserving the zero-newly-allocated-holes behavior."
    }
  ],
  "id": "CVE-2026-72353",
  "lastModified": "2026-08-17T06:18:39.410",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:22:08.730",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3dd3e43f17cda174009a51fe668046ed7afef46a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/88496c4ac5a6ade75619f4b1015706a8b924d50a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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