FKIE_CVE-2026-64533

Vulnerability from fkie_nvd - Published: 2026-07-27 08:16 - Updated: 2026-08-17 05:17
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/159f694d682e4215b3822ae31ed3a4631628fe55
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/32b9f8733feb241627fa5f564b1a99b5cae974c5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/57c071e2c4f30b9c6f5aacb6679aab1269fbae99
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6a4c53a2e26a865565bd6a460961e8d6fcb32329
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7adb38279812c9c06b0e3fa7382f4d7887f3fa2d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ca343a99806b4fc8e27c48f08be3445c5fcd1445
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ddfc8683e1a627dbf1b83bacf8961443dd654258
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs3/fslog.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ca343a99806b4fc8e27c48f08be3445c5fcd1445",
              "status": "affected",
              "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
              "versionType": "git"
            },
            {
              "lessThan": "ddfc8683e1a627dbf1b83bacf8961443dd654258",
              "status": "affected",
              "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
              "versionType": "git"
            },
            {
              "lessThan": "57c071e2c4f30b9c6f5aacb6679aab1269fbae99",
              "status": "affected",
              "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
              "versionType": "git"
            },
            {
              "lessThan": "159f694d682e4215b3822ae31ed3a4631628fe55",
              "status": "affected",
              "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
              "versionType": "git"
            },
            {
              "lessThan": "7adb38279812c9c06b0e3fa7382f4d7887f3fa2d",
              "status": "affected",
              "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
              "versionType": "git"
            },
            {
              "lessThan": "32b9f8733feb241627fa5f564b1a99b5cae974c5",
              "status": "affected",
              "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
              "versionType": "git"
            },
            {
              "lessThan": "6a4c53a2e26a865565bd6a460961e8d6fcb32329",
              "status": "affected",
              "version": "b46acd6a6a627d876898e1c84d3f84902264b445",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ntfs3/fslog.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": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "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\nfs/ntfs3: validate lcns_follow in log_replay conversion\n\nlog_replay() converts DIR_PAGE_ENTRY_32 records into DIR_PAGE_ENTRY\nrecords when replaying version 0 restart tables.\n\nDuring this conversion, the memmove() length is derived directly from\nthe on-disk lcns_follow field:\n\n\tmemmove(\u0026dp-\u003evcn, \u0026dp0-\u003evcn_low,\n\t\t2 * sizeof(u64) +\n\t\t\t\tle32_to_cpu(dp-\u003elcns_follow) * sizeof(u64));\n\ncheck_rstbl() validates restart table structure, but does not constrain\nper-entry lcns_follow values relative to the entry size. A malformed\nfilesystem image can provide an oversized lcns_follow value, causing\nthe conversion memmove() to access memory beyond the bounds of the\nallocated restart table buffer.\n\nThe same field is later used to bound iteration over page_lcns[],\nso validating lcns_follow during conversion also prevents downstream\nout-of-bounds access from the same malformed metadata.\n\nCompute the maximum valid lcns_follow from the already-validated\nrestart table entry size and reject entries that exceed this bound.\nReuse the existing t16/t32 scratch variables already declared in\nlog_replay() to avoid introducing new declarations.\n\n[almaz.alexandrovich@paragon-software.com: fixed the conflicts]"
    }
  ],
  "id": "CVE-2026-64533",
  "lastModified": "2026-08-17T05:17:58.350",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-27T08:16:22.510",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/159f694d682e4215b3822ae31ed3a4631628fe55"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/32b9f8733feb241627fa5f564b1a99b5cae974c5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/57c071e2c4f30b9c6f5aacb6679aab1269fbae99"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6a4c53a2e26a865565bd6a460961e8d6fcb32329"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7adb38279812c9c06b0e3fa7382f4d7887f3fa2d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ca343a99806b4fc8e27c48f08be3445c5fcd1445"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ddfc8683e1a627dbf1b83bacf8961443dd654258"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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