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GHSA-3HCX-97MC-6XWW

Vulnerability from github – Published: 2026-10-28 12:31 – Updated: 2026-10-28 12:31

Details

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

ksmbd: zero the FS_OBJECT_ID_INFORMATION buffer before filling it in

smb2_get_info_filesystem() reports 64 bytes for FS_OBJECT_ID_INFORMATION, that is the whole of struct object_id_info, but writes only 46 of them:

objid[] is 16 bytes, and when the volume UUID is not available only sizeof(stfs.f_fsid) (8) bytes are copied into it;
extended_info.version_string[] is STRING_LENGTH (28) bytes, and only strlen("1.1.0") (5) bytes are copied into it.

The response buffer is zeroed on allocation (kvzalloc() in smb2_allocate_rsp_buf()), so for a standalone request the remaining 31 bytes are zero. In a compound request they need not be. The offset of the next response is advanced by the length pinned for the previous one, so if a preceding command wrote its reply into the buffer and then failed, smb2_set_err_rsp() pins only the short error response and the next reply lands inside the area that has already been written. Only the header is cleared there:

memset((char *)rsp_hdr, 0, sizeof(struct smb2_hdr) + 2);

The client then receives up to 31 bytes of a response it was not meant to see, including one that failed with an access denied error.

Clear the structure before filling it in. As a side effect version_string is now NUL terminated.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-99113"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-28T11:17:30Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: zero the FS_OBJECT_ID_INFORMATION buffer before filling it in\n\nsmb2_get_info_filesystem() reports 64 bytes for FS_OBJECT_ID_INFORMATION,\nthat is the whole of struct object_id_info, but writes only 46 of them:\n\n - objid[] is 16 bytes, and when the volume UUID is not available only\n   sizeof(stfs.f_fsid) (8) bytes are copied into it;\n - extended_info.version_string[] is STRING_LENGTH (28) bytes, and only\n   strlen(\"1.1.0\") (5) bytes are copied into it.\n\nThe response buffer is zeroed on allocation (kvzalloc() in\nsmb2_allocate_rsp_buf()), so for a standalone request the remaining 31\nbytes are zero.  In a compound request they need not be.  The offset of\nthe next response is advanced by the length pinned for the previous one,\nso if a preceding command wrote its reply into the buffer and then\nfailed, smb2_set_err_rsp() pins only the short error response and the\nnext reply lands inside the area that has already been written.  Only\nthe header is cleared there:\n\n\tmemset((char *)rsp_hdr, 0, sizeof(struct smb2_hdr) + 2);\n\nThe client then receives up to 31 bytes of a response it was not meant\nto see, including one that failed with an access denied error.\n\nClear the structure before filling it in.  As a side effect\nversion_string is now NUL terminated.",
  "id": "GHSA-3hcx-97mc-6xww",
  "modified": "2026-10-28T12:31:03Z",
  "published": "2026-10-28T12:31:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99113"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/015fffa48e96ca8d73a627445341ccff86b02251"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/399aa12450a61a5c73dc77e73f069ece9687c95d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/898cb4f2e12a5ddea1b2d821cc642c3100f46da7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-99113 (GCVE-0-2026-99113)

Vulnerability from cvelistv5 – Published: 2026-10-28 10:34 – Updated: 2026-10-28 10:34

Title

ksmbd: zero the FS_OBJECT_ID_INFORMATION buffer before filling it in

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: zero the FS_OBJECT_ID_INFORMATION buffer before filling it in smb2_get_info_filesystem() reports 64 bytes for FS_OBJECT_ID_INFORMATION, that is the whole of struct object_id_info, but writes only 46 of them: - objid[] is 16 bytes, and when the volume UUID is not available only sizeof(stfs.f_fsid) (8) bytes are copied into it; - extended_info.version_string[] is STRING_LENGTH (28) bytes, and only strlen("1.1.0") (5) bytes are copied into it. The response buffer is zeroed on allocation (kvzalloc() in smb2_allocate_rsp_buf()), so for a standalone request the remaining 31 bytes are zero. In a compound request they need not be. The offset of the next response is advanced by the length pinned for the previous one, so if a preceding command wrote its reply into the buffer and then failed, smb2_set_err_rsp() pins only the short error response and the next reply lands inside the area that has already been written. Only the header is cleared there: memset((char *)rsp_hdr, 0, sizeof(struct smb2_hdr) + 2); The client then receives up to 31 bytes of a response it was not meant to see, including one that failed with an access denied error. Clear the structure before filling it in. As a side effect version_string is now NUL terminated.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7033 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/898cb4f2e12a5ddea…
https://git.kernel.org/stable/c/015fffa48e96ca8d7…
https://git.kernel.org/stable/c/399aa12450a61a5c7…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 898cb4f2e12a5ddea1b2d821cc642c3100f46da7 (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 015fffa48e96ca8d73a627445341ccff86b02251 (git) Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 399aa12450a61a5c73dc77e73f069ece9687c95d (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 6.18.59 , ≤ 6.18.* (semver) Unaffected: 7.2.13 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "898cb4f2e12a5ddea1b2d821cc642c3100f46da7",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "015fffa48e96ca8d73a627445341ccff86b02251",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "399aa12450a61a5c73dc77e73f069ece9687c95d",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.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": "6.18.*",
              "status": "unaffected",
              "version": "6.18.59",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.59",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "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: zero the FS_OBJECT_ID_INFORMATION buffer before filling it in\n\nsmb2_get_info_filesystem() reports 64 bytes for FS_OBJECT_ID_INFORMATION,\nthat is the whole of struct object_id_info, but writes only 46 of them:\n\n - objid[] is 16 bytes, and when the volume UUID is not available only\n   sizeof(stfs.f_fsid) (8) bytes are copied into it;\n - extended_info.version_string[] is STRING_LENGTH (28) bytes, and only\n   strlen(\"1.1.0\") (5) bytes are copied into it.\n\nThe response buffer is zeroed on allocation (kvzalloc() in\nsmb2_allocate_rsp_buf()), so for a standalone request the remaining 31\nbytes are zero.  In a compound request they need not be.  The offset of\nthe next response is advanced by the length pinned for the previous one,\nso if a preceding command wrote its reply into the buffer and then\nfailed, smb2_set_err_rsp() pins only the short error response and the\nnext reply lands inside the area that has already been written.  Only\nthe header is cleared there:\n\n\tmemset((char *)rsp_hdr, 0, sizeof(struct smb2_hdr) + 2);\n\nThe client then receives up to 31 bytes of a response it was not meant\nto see, including one that failed with an access denied error.\n\nClear the structure before filling it in.  As a side effect\nversion_string is now NUL terminated."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-28T10:34:30.767Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/898cb4f2e12a5ddea1b2d821cc642c3100f46da7"
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          "url": "https://git.kernel.org/stable/c/015fffa48e96ca8d73a627445341ccff86b02251"
        },
        {
          "url": "https://git.kernel.org/stable/c/399aa12450a61a5c73dc77e73f069ece9687c95d"
        }
      ],
      "title": "ksmbd: zero the FS_OBJECT_ID_INFORMATION buffer before filling it in",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
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    "assignerShortName": "Linux",
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    "datePublished": "2026-10-28T10:34:30.767Z",
    "dateReserved": "2026-09-25T10:25:14.392Z",
    "dateUpdated": "2026-10-28T10:34:30.767Z",
    "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.

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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.
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