CVE-2026-72353 (GCVE-0-2026-72353)
Vulnerability from cvelistv5
Published
2026-08-15 05:55
Modified
2026-08-17 05:43
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.
Impacted products
Vendor Product Version
Linux Linux Version: 495e90fa334828d4119061e2726af51d0a0fb4ed
Version: 495e90fa334828d4119061e2726af51d0a0fb4ed
Create a notification for this product.
Show details on NVD website


{
  "containers": {
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - Remote clients can reach ntfs_attr_fallocate via ksmbd or nfsd vfs_fallocate on NTFS-backed shares, while concurrent SMB/NFS writes trigger ntfs_attr_map_cluster/ntfs_runlists_merge to free the runlist during fallocate.\nAC:L - The attacker controls both race sides with parallel fallocate and write/mmap requests on the same NTFS file; the fix commit documents a reproducible KASAN slab-use-after-free from this attacker-driven concurrency.\nPR:L - Only write permission on a regular file on a mounted NTFS volume is required (local unprivileged user or authenticated SMB/NFS client), not real root in the initial mount namespace.\nUI:N - No victim interaction is needed during exploitation; the attacker prepares sparse/hole file state and drives fallocate plus concurrent writes without requiring another user to mount or open files.\nS:U - Impact is kernel heap corruption and privilege escalation within the host; it does not cross VM, hypervisor, or IOMMU security boundaries.\nC:H - Slab use-after-free on runlist_element fields (rl-\u003elcn, rl-\u003elength, rl-\u003evcn) reads freed kernel memory, enabling standard UAF-based arbitrary read and kernel pointer disclosure primitives.\nI:H - Freed runlist metadata influences subsequent cluster allocation and ntfs_dio_zero_range operations, providing UAF-based heap manipulation and arbitrary kernel write exploitation potential.\nA:H - Reproduced as KASAN slab-use-after-free in ntfs_attr_fallocate; stale runlist dereference can cause kernel oops, BUG, or panic when the race succeeds."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:43:11.052Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3dd3e43f17cda174009a51fe668046ed7afef46a"
        },
        {
          "url": "https://git.kernel.org/stable/c/88496c4ac5a6ade75619f4b1015706a8b924d50a"
        }
      ],
      "title": "ntfs: avoid stale runlist element dereference in fallocate",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72353",
    "datePublished": "2026-08-15T05:55:55.480Z",
    "dateReserved": "2026-08-09T03:40:39.921Z",
    "dateUpdated": "2026-08-17T05:43:11.052Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

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.


Loading…

Loading…