CVE-2026-64379 (GCVE-0-2026-64379)
Vulnerability from cvelistv5
Published
2026-07-25 08:50
Modified
2026-08-17 04:54
Severity ?
7.1 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: mask server-provided mode to 07777 in modefromsid When modefromsid is active, parse_dacl() applies the server-provided sub_auth[2] value from the NFS mode SID to cf_mode without masking to 07777. Apply the correct masking, same as in the read path.
References
Impacted products
Vendor Product Version
Linux Linux Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
Version: e2f8fbfb8d09c06decde162090fac3ee220aa280
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cifsacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
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            }
          ]
        },
        {
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.4"
            },
            {
              "lessThan": "5.4",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "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": "6.12.96",
              "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",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.261",
                  "versionStartIncluding": "5.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "5.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "5.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "5.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "5.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
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                },
                {
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                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "5.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: mask server-provided mode to 07777 in modefromsid\n\nWhen modefromsid is active, parse_dacl() applies the server-provided\nsub_auth[2] value from the NFS mode SID to cf_mode without masking to\n07777. Apply the correct masking, same as in the read path."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - A malicious or compromised SMB server can supply the crafted NFS mode SID through a network-delivered QUERY_INFO security descriptor.\nAC:L - With modefromsid enabled, the server directly controls sub_auth[2], and the invalid inode-type bits are applied deterministically without a race or memory-layout dependency.\nPR:N - The attacker acting as the SMB server needs no privileges on the client; client authentication to the share is a victim-side condition rather than an attacker privilege.\nUI:R - A victim administrator or service must mount the SMB share with modefromsid, or subsequently access a crafted object on an existing mount.\nS:U - The corrupted mode and resulting VFS behavior remain within the Linux kernel\u0027s existing security authority and do not cross a VM, IOMMU, or sandbox boundary.\nC:N - The flaw only injects bits into the 16-bit mode field and provides no out-of-bounds read, memory disclosure, or direct mechanism for returning client data to the attacker.\nI:L - The attacker can alter S_IFMT bits in cf_mode and thereby change the inode\u0027s perceived type and selected VFS operations, but this is a constrained metadata modification rather than an arbitrary write or control-flow primitive.\nA:H - Forging the root or widespread inode types can prevent the share from mounting or render its objects unusable; for CIFS-root or critical SMB-backed deployments this can cause complete service availability loss."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:54:30.613Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14"
        },
        {
          "url": "https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94"
        },
        {
          "url": "https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78"
        },
        {
          "url": "https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d"
        },
        {
          "url": "https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d"
        },
        {
          "url": "https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954"
        },
        {
          "url": "https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151"
        }
      ],
      "title": "smb: client: mask server-provided mode to 07777 in modefromsid",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64379",
    "datePublished": "2026-07-25T08:50:29.717Z",
    "dateReserved": "2026-07-19T15:36:31.784Z",
    "dateUpdated": "2026-08-17T04:54:30.613Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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