Vulnerability-Lookup

GHSA-HMFM-F852-MMJ6

Vulnerability from github – Published: 2026-08-28 09:31 – Updated: 2026-08-29 09:30

Details

In the Linux kernel, the following vulnerability has been resolved:

ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()

When resolving an attribute lookup with a non-zero @lowest_vcn, ntfs_external_attr_find() peeks at the next $ATTRIBUTE_LIST entry to decide whether to keep searching, but bounds that not-yet-validated entry only with "(u8 )next_al_entry + 6 < al_end" (which proves just bytes 0..6 are in range) and "(u8 )next_al_entry + length <= al_end" with an attacker-controlled, non-8-aligned length. It then reads next_al_entry->lowest_vcn (an __le64 at offset 8) and the name at next_al_entry->name_offset, both of which can lie past al_end -- the exact end of the kvmalloc'd attribute-list buffer (allocated at the on-disk attr_list_size, no rounding). A crafted on-disk $ATTRIBUTE_LIST whose last entry sits a few bytes before al_end therefore yields a slab out-of-bounds read when the inode is read.

Validate the look-ahead entry with ntfs_attr_list_entry_is_valid() (added in patch 1/3) before dereferencing lowest_vcn and the name, so the same fixed-header, length and name bounds the main attribute-list walk uses now guard this read too.

Severity

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80673"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-28T08:16:52Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()\n\nWhen resolving an attribute lookup with a non-zero @lowest_vcn,\nntfs_external_attr_find() peeks at the next $ATTRIBUTE_LIST entry to\ndecide whether to keep searching, but bounds that not-yet-validated\nentry only with \"(u8 *)next_al_entry + 6 \u003c al_end\" (which proves just\nbytes 0..6 are in range) and \"(u8 *)next_al_entry + length \u003c= al_end\"\nwith an attacker-controlled, non-8-aligned length. It then reads\nnext_al_entry-\u003elowest_vcn (an __le64 at offset 8) and the name at\nnext_al_entry-\u003ename_offset, both of which can lie past al_end -- the\nexact end of the kvmalloc\u0027d attribute-list buffer (allocated at the\non-disk attr_list_size, no rounding). A crafted on-disk $ATTRIBUTE_LIST\nwhose last entry sits a few bytes before al_end therefore yields a slab\nout-of-bounds read when the inode is read.\n\nValidate the look-ahead entry with ntfs_attr_list_entry_is_valid() (added\nin patch 1/3) before dereferencing lowest_vcn and the name, so the same\nfixed-header, length and name bounds the main attribute-list walk uses now\nguard this read too.",
  "id": "GHSA-hmfm-f852-mmj6",
  "modified": "2026-08-29T09:30:27Z",
  "published": "2026-08-28T09:31:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80673"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/344b18f389f9934d59c7b0cf3d20541ea2e0da58"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/44885c9b45eb4082fb7f558590d84bb254a08e94"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-80673 (GCVE-0-2026-80673)

Vulnerability from cvelistv5 – Published: 2026-08-28 06:49 – Updated: 2026-08-29 06:22

Title

ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()

Summary

In the Linux kernel, the following vulnerability has been resolved: ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find() When resolving an attribute lookup with a non-zero @lowest_vcn, ntfs_external_attr_find() peeks at the next $ATTRIBUTE_LIST entry to decide whether to keep searching, but bounds that not-yet-validated entry only with "(u8 *)next_al_entry + 6 < al_end" (which proves just bytes 0..6 are in range) and "(u8 *)next_al_entry + length <= al_end" with an attacker-controlled, non-8-aligned length. It then reads next_al_entry->lowest_vcn (an __le64 at offset 8) and the name at next_al_entry->name_offset, both of which can lie past al_end -- the exact end of the kvmalloc'd attribute-list buffer (allocated at the on-disk attr_list_size, no rounding). A crafted on-disk $ATTRIBUTE_LIST whose last entry sits a few bytes before al_end therefore yields a slab out-of-bounds read when the inode is read. Validate the look-ahead entry with ntfs_attr_list_entry_is_valid() (added in patch 1/3) before dereferencing lowest_vcn and the name, so the same fixed-header, length and name bounds the main attribute-list walk uses now guard this read too.

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/44885c9b45eb4082f…
https://git.kernel.org/stable/c/344b18f389f9934d5…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 , < 44885c9b45eb4082fb7f558590d84bb254a08e94 (git) Affected: 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 , < 344b18f389f9934d59c7b0cf3d20541ea2e0da58 (git)
Linux	Linux	Affected: 7.1 Unaffected: 0 , < 7.1 (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "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": "44885c9b45eb4082fb7f558590d84bb254a08e94",
              "status": "affected",
              "version": "1e9ea7e04472d4e5e12e58c881eaacfb3e49b669",
              "versionType": "git"
            },
            {
              "lessThan": "344b18f389f9934d59c7b0cf3d20541ea2e0da58",
              "status": "affected",
              "version": "1e9ea7e04472d4e5e12e58c881eaacfb3e49b669",
              "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: bound the look-ahead attribute-list entry in ntfs_external_attr_find()\n\nWhen resolving an attribute lookup with a non-zero @lowest_vcn,\nntfs_external_attr_find() peeks at the next $ATTRIBUTE_LIST entry to\ndecide whether to keep searching, but bounds that not-yet-validated\nentry only with \"(u8 *)next_al_entry + 6 \u003c al_end\" (which proves just\nbytes 0..6 are in range) and \"(u8 *)next_al_entry + length \u003c= al_end\"\nwith an attacker-controlled, non-8-aligned length. It then reads\nnext_al_entry-\u003elowest_vcn (an __le64 at offset 8) and the name at\nnext_al_entry-\u003ename_offset, both of which can lie past al_end -- the\nexact end of the kvmalloc\u0027d attribute-list buffer (allocated at the\non-disk attr_list_size, no rounding). A crafted on-disk $ATTRIBUTE_LIST\nwhose last entry sits a few bytes before al_end therefore yields a slab\nout-of-bounds read when the inode is read.\n\nValidate the look-ahead entry with ntfs_attr_list_entry_is_valid() (added\nin patch 1/3) before dereferencing lowest_vcn and the name, so the same\nfixed-header, length and name bounds the main attribute-list walk uses now\nguard this read too."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - Classic NTFS registers ntfs_export_ops; remote nfsd/ksmbd VFS reads/lookups on an exported crafted NTFS volume reach ntfs_attr_lookup(lowest_vcn!=0)-\u003entfs_external_attr_find() without local syscall access on the victim host.\nAC:L - Attacker fully controls on-disk $ATTRIBUTE_LIST tail geometry (short look-ahead entry length/placement); weak bounds let lowest_vcn/name reads pass al_end deterministically on walks with non-zero lowest_vcn, with no race or uncontrollable layout.\nPR:N - Per kernel CNA crafted-filesystem model, exploitation needs only supplying a malicious NTFS image (USB/automount) or read access to mounted/exported NTFS content to trigger extent lookups; no init-namespace root or CAP_SYS_ADMIN on the lookup/read path.\nUI:N - udisks2/systemd automount of removable NTFS and remote NFS/SMB reads on exported volumes reach the vulnerable attribute-list look-ahead during normal file/inode access without the victim deliberately mounting images or performing attacker-specific actions.\nS:U - Slab out-of-bounds read and possible kernel crash stay within the mounting host kernel; this is standard filesystem parsing, not a VM escape, IOMMU bypass, or cross-sandbox scope change.\nC:H - Unvalidated look-ahead reads next_al_entry-\u003elowest_vcn and the Unicode name past the kvmalloc attribute-list end (allocated at exact attr_list_size), disclosing adjacent slab heap memory beyond a few bytes.\nI:H - Attacker-controlled look-ahead entry fields drive kernel parsing of forged attribute-list metadata and adjacent slab contents; per CNA guidance this memory-corruption class can be leveraged for arbitrary kernel modification or control-flow hijack.\nA:H - Slab out-of-bounds read from the attribute-list buffer during inode/extent resolution can access unmapped adjacent memory and oops or panic the kernel, fully denying availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-29T06:22:00.387Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/44885c9b45eb4082fb7f558590d84bb254a08e94"
        },
        {
          "url": "https://git.kernel.org/stable/c/344b18f389f9934d59c7b0cf3d20541ea2e0da58"
        }
      ],
      "title": "ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80673",
    "datePublished": "2026-08-28T06:49:12.951Z",
    "dateReserved": "2026-08-26T14:34:25.782Z",
    "dateUpdated": "2026-08-29T06:22:00.387Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-HMFM-F852-MMJ6

CVE-2026-80673 (GCVE-0-2026-80673)

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Sightings

Nomenclature