Skip to content
Heist/ feed
Back to feed
HighFix available

fs/ntfs3: validate lcns_follow in log_replay conversion

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: validate lcns_follow in log_replay conversion log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY records when replaying version 0 restart tables. During this conversion, the memmove() length is derived directly from the on-disk lcns_follow field: memmove(&dp->vcn, &dp0->vcn_low, 2 * sizeof(u64) + le32_to_cpu(dp->lcns_follow) * sizeof(u64)); check_rstbl() validates restart table structure, but does not constrain per-entry lcns_follow values relative to the entry size. A malformed filesystem image can provide an oversized lcns_follow value, causing the conversion memmove() to access memory beyond the bounds of the allocated restart table buffer. The same field is later used to bound iteration over page_lcns[], so validating lcns_follow during conversion also prevents downstream out-of-bounds access from the same malformed metadata. Compute the maximum valid lcns_follow from the already-validated restart table entry size and reject entries that exceed this bound. Reuse the existing t16/t32 scratch variables already declared in log_replay() to avoid introducing new declarations. [almaz.alexandrovich@paragon-software.com: fixed the conflicts]

Products
Kernel
Affected versions
Not specified
Fixed versions
5.15.212, 6.1.178, 6.12.97, 6.18.40, 6.6.145, 7.1.5
CVEs
CVE-2026-64533
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 10:26 UTC · Revision 1

Source evidence

fs/ntfs3: validate lcns_follow in log_replay conversion

core-osv · Original source

Published 27 Jul 2026, 06:32 UTC

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: validate lcns_follow in log_replay conversion log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY records when replaying version 0 restart tables. During this conversion, the memmove() length is derived directly from the on-disk lcns_follow field: memmove(&dp->vcn, &dp0->vcn_low, 2 * sizeof(u64) + le32_to_cpu(dp->lcns_follow) * sizeof(u64)); check_rstbl() validates restart table structure, but does not constrain per-entry lcns_follow values relative to the entry size. A malformed filesystem image can provide an oversized lcns_follow value, causing the conversion memmove() to access memory beyond the bounds of the allocated restart table buffer. The same field is later used to bound iteration over page_lcns[], so validating lcns_follow during conversion also prevents downstream out-of-bounds access from the same malformed metadata. Compute the maximum valid lcns_follow from the already-validated restart table entry size and reject entries that exceed this bound. Reuse the existing t16/t32 scratch variables already declared in log_replay() to avoid introducing new declarations. [almaz.alexandrovich@paragon-software.com: fixed the conflicts]

osv:CVE-2026-64533

Kernel

Fixed versions: 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5

Complete source record
{
  "id": "181418d54511301d5d3e32ae9f4a1cb65094a4ea2a2d6e7c697510bafe4b4a39",
  "url": "https://osv.dev/vulnerability/CVE-2026-64533",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "fs/ntfs3: validate lcns_follow in log_replay conversion",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: validate lcns_follow in log_replay conversion log_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY records when replaying version 0 restart tables. During this conversion, the memmove() length is derived directly from the on-disk lcns_follow field: memmove(&dp->vcn, &dp0->vcn_low, 2 * sizeof(u64) + le32_to_cpu(dp->lcns_follow) * sizeof(u64)); check_rstbl() validates restart table structure, but does not constrain per-entry lcns_follow values relative to the entry size. A malformed filesystem image can provide an oversized lcns_follow value, causing the conversion memmove() to access memory beyond the bounds of the allocated restart table buffer. The same field is later used to bound iteration over page_lcns[], so validating lcns_follow during conversion also prevents downstream out-of-bounds access from the same malformed metadata. Compute the maximum valid lcns_follow from the already-validated restart table entry size and reject entries that exceed this bound. Reuse the existing t16/t32 scratch variables already declared in log_replay() to avoid introducing new declarations. [almaz.alexandrovich@paragon-software.com: fixed the conflicts]",
    "evidence": "osv:CVE-2026-64533",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.212",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-64533",
      "aliases": [
        "CVE-2026-64533"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "b46acd6a6a627d876898e1c84d3f84902264b445"
                },
                {
                  "fixed": "ca343a99806b4fc8e27c48f08be3445c5fcd1445"
                },
                {
                  "fixed": "ddfc8683e1a627dbf1b83bacf8961443dd654258"
                },
                {
                  "fixed": "57c071e2c4f30b9c6f5aacb6679aab1269fbae99"
                },
                {
                  "fixed": "159f694d682e4215b3822ae31ed3a4631628fe55"
                },
                {
                  "fixed": "7adb38279812c9c06b0e3fa7382f4d7887f3fa2d"
                },
                {
                  "fixed": "32b9f8733feb241627fa5f564b1a99b5cae974c5"
                },
                {
                  "fixed": "6a4c53a2e26a865565bd6a460961e8d6fcb32329"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64533.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.15.0"
                },
                {
                  "fixed": "5.15.212"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.178"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.145"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.97"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.40"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64533.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.866468152Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/159f694d682e4215b3822ae31ed3a4631628fe55",
        "https://git.kernel.org/stable/c/32b9f8733feb241627fa5f564b1a99b5cae974c5",
        "https://git.kernel.org/stable/c/57c071e2c4f30b9c6f5aacb6679aab1269fbae99",
        "https://git.kernel.org/stable/c/6a4c53a2e26a865565bd6a460961e8d6fcb32329",
        "https://git.kernel.org/stable/c/7adb38279812c9c06b0e3fa7382f4d7887f3fa2d",
        "https://git.kernel.org/stable/c/ca343a99806b4fc8e27c48f08be3445c5fcd1445",
        "https://git.kernel.org/stable/c/ddfc8683e1a627dbf1b83bacf8961443dd654258",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64533.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64533",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64533.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64533",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 494497,
  "published_at": "2026-07-27T06:32:33.74+00:00"
}