CVE-2026-64533 (GCVE-0-2026-64533)
Vulnerability from cvelistv5
Published
2026-07-27 06:32
Modified
2026-08-17 04:57
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
Impacted products
Vendor Product Version
Linux Linux Version: b46acd6a6a627d876898e1c84d3f84902264b445
Version: b46acd6a6a627d876898e1c84d3f84902264b445
Version: b46acd6a6a627d876898e1c84d3f84902264b445
Version: b46acd6a6a627d876898e1c84d3f84902264b445
Version: b46acd6a6a627d876898e1c84d3f84902264b445
Version: b46acd6a6a627d876898e1c84d3f84902264b445
Version: b46acd6a6a627d876898e1c84d3f84902264b445
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "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 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]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The NTFS3 parser consumes malicious metadata from a locally mounted block device or filesystem image, not directly through a network protocol.\nAC:L - A structurally valid 44-byte entry with attacker-controlled lcns_follow=2 already crosses the heap-buffer boundary. No race or uncontrollable condition is required.\nPR:N - The attacker needs no account or capability to prepare and supply the crafted image; the init-namespace CAP_SYS_ADMIN mount requirement applies to the interacting victim or privileged mounting helper.\nUI:R - A victim or trusted mounting helper must cause the crafted NTFS filesystem to be mounted before journal replay processes the malicious metadata.\nS:U - The corruption compromises the kernel processing its own filesystem metadata and does not cross a distinct security authority such as a guest-to-host boundary.\nC:H - The attacker-controlled memmove performs a heap out-of-bounds read of attacker-selected extent, and the resulting memory corruption can be leveraged to disclose kernel memory.\nI:H - The same memmove writes beyond the allocated restart-table buffer, allowing corruption of adjacent slab objects and potentially arbitrary writes or control-flow hijacking.\nA:H - A sufficiently large lcns_follow reliably drives the kernel into an extensive invalid memory access, causing an oops or panic during mount and permitting repeated denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:57:11.184Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ca343a99806b4fc8e27c48f08be3445c5fcd1445"
        },
        {
          "url": "https://git.kernel.org/stable/c/ddfc8683e1a627dbf1b83bacf8961443dd654258"
        },
        {
          "url": "https://git.kernel.org/stable/c/57c071e2c4f30b9c6f5aacb6679aab1269fbae99"
        },
        {
          "url": "https://git.kernel.org/stable/c/159f694d682e4215b3822ae31ed3a4631628fe55"
        },
        {
          "url": "https://git.kernel.org/stable/c/7adb38279812c9c06b0e3fa7382f4d7887f3fa2d"
        },
        {
          "url": "https://git.kernel.org/stable/c/32b9f8733feb241627fa5f564b1a99b5cae974c5"
        },
        {
          "url": "https://git.kernel.org/stable/c/6a4c53a2e26a865565bd6a460961e8d6fcb32329"
        }
      ],
      "title": "fs/ntfs3: validate lcns_follow in log_replay conversion",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64533",
    "datePublished": "2026-07-27T06:32:33.740Z",
    "dateReserved": "2026-07-19T15:36:31.795Z",
    "dateUpdated": "2026-08-17T04:57:11.184Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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