Vulnerability-Lookup

CVE-2026-64391 (GCVE-0-2026-64391)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-07-27 05:00

Title

ksmbd: use opener credentials for ADS I/O

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for ADS I/O Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials. Run ADS I/O with the credentials captured when the SMB handle was opened.

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

References

4 references

URL	Tags
https://git.kernel.org/stable/c/a8f5d39971bbad934…
https://git.kernel.org/stable/c/2b4592cea214683de…
https://git.kernel.org/stable/c/52a56cf53ec834c44…
https://git.kernel.org/stable/c/baa5e094886fffa7e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f44158485826c076335d6860d35872271a83791d , < a8f5d39971bbad9340d49cd41b0e2da9452a649d (git) Affected: f44158485826c076335d6860d35872271a83791d , < 2b4592cea214683de0f2ce6f8c22c097fb0ea1ab (git) Affected: f44158485826c076335d6860d35872271a83791d , < 52a56cf53ec834c44ac1b4d16d585f26613ee5ce (git) Affected: f44158485826c076335d6860d35872271a83791d , < baa5e094886fffa7e6272edcb5e08be5ce28262c (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/vfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a8f5d39971bbad9340d49cd41b0e2da9452a649d",
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "versionType": "git"
            },
            {
              "lessThan": "2b4592cea214683de0f2ce6f8c22c097fb0ea1ab",
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "versionType": "git"
            },
            {
              "lessThan": "52a56cf53ec834c44ac1b4d16d585f26613ee5ce",
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "versionType": "git"
            },
            {
              "lessThan": "baa5e094886fffa7e6272edcb5e08be5ce28262c",
              "status": "affected",
              "version": "f44158485826c076335d6860d35872271a83791d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/vfs.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": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc1",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use opener credentials for ADS I/O\n\nAlternate data streams are stored as xattrs. Unlike regular file I/O,\ntheir read and write paths therefore call VFS xattr helpers which recheck\ninode permissions and LSM policy using the current task credentials.\n\nRun ADS I/O with the credentials captured when the SMB handle was opened."
        }
      ],
      "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"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-27T05:00:20.631Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d"
        },
        {
          "url": "https://git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab"
        },
        {
          "url": "https://git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce"
        },
        {
          "url": "https://git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c"
        }
      ],
      "title": "ksmbd: use opener credentials for ADS I/O",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64391",
    "datePublished": "2026-07-25T08:50:38.013Z",
    "dateReserved": "2026-07-19T15:36:31.785Z",
    "dateUpdated": "2026-07-27T05:00:20.631Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-64391",
      "date": "2026-07-27",
      "epss": "0.00457",
      "percentile": "0.37245"
    },
    "microsoft_vex": {
      "current_release_date": "2026-07-26T01:11:39.000Z",
      "cve": "CVE-2026-64391",
      "id": "msrc_CVE-2026-64391",
      "initial_release_date": "2026-07-26T01:11:39.000Z",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "ksmbd: use opener credentials for ADS I/O",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64391.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-64391\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-07-25T10:17:22.453\",\"lastModified\":\"2026-07-27T05:16:45.943\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nksmbd: use opener credentials for ADS I/O\\n\\nAlternate data streams are stored as xattrs. Unlike regular file I/O,\\ntheir read and write paths therefore call VFS xattr helpers which recheck\\ninode permissions and LSM policy using the current task credentials.\\n\\nRun ADS I/O with the credentials captured when the SMB handle was opened.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/smb/server/vfs.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"f44158485826c076335d6860d35872271a83791d\",\"lessThan\":\"a8f5d39971bbad9340d49cd41b0e2da9452a649d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f44158485826c076335d6860d35872271a83791d\",\"lessThan\":\"2b4592cea214683de0f2ce6f8c22c097fb0ea1ab\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f44158485826c076335d6860d35872271a83791d\",\"lessThan\":\"52a56cf53ec834c44ac1b4d16d585f26613ee5ce\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f44158485826c076335d6860d35872271a83791d\",\"lessThan\":\"baa5e094886fffa7e6272edcb5e08be5ce28262c\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/smb/server/vfs.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.15\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.15\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.96\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.39\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.4\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-07-25T16:00:13Z",
      "cve": "CVE-2026-64391",
      "id": "CVE-2026-64391",
      "initial_release_date": "2026-07-25T16:00:13Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-64391",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-64391.json",
      "version": "2"
    }
  }
}

GHSA-83MF-WFC5-X4X3

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-27 06:30

Details

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

ksmbd: use opener credentials for ADS I/O

Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials.

Run ADS I/O with the credentials captured when the SMB handle was opened.

Severity

9.8 (Critical)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64391"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:22Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use opener credentials for ADS I/O\n\nAlternate data streams are stored as xattrs. Unlike regular file I/O,\ntheir read and write paths therefore call VFS xattr helpers which recheck\ninode permissions and LSM policy using the current task credentials.\n\nRun ADS I/O with the credentials captured when the SMB handle was opened.",
  "id": "GHSA-83mf-wfc5-x4x3",
  "modified": "2026-07-27T06:30:35Z",
  "published": "2026-07-25T12:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64391"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c"
    }
  ],
  "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"
    }
  ]
}

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.

Action not permitted

CVE-2026-64391 (GCVE-0-2026-64391)

GHSA-83MF-WFC5-X4X3

Tags

Sightings

Nomenclature