CVE-2026-93801 (GCVE-0-2026-93801)
Vulnerability from cvelistv5
Published
2026-09-24 16:02
Modified
2026-10-21 12:52
Severity ?
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb/client: zero-initialize stack-allocated cifs_open_info_data Stack-allocated cifs_open_info_data may contain random data. This can make some fields have wrong value if they are not set later.
References
Impacted products
Vendor Product Version
Linux Linux Version: 436cfdbc57d98808fce427d9a8d97691374989b3
Version: fc2f2011d3d84b56f536b4a25a4bb2fa1b13d520
Version: 057ac50638bcece64b3b436d3a61b70ed6c01a34
Version: 057ac50638bcece64b3b436d3a61b70ed6c01a34
Version: 83d3bc866530a36a465b47cce4d2a9def2411960
Version: 6.6.113   ≤
Version: 6.12.54   ≤
Version: 6.17.4   ≤
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/link.c",
            "fs/smb/client/smb1ops.c",
            "fs/smb/client/smb2ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "436cfdbc57d98808fce427d9a8d97691374989b3",
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              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "057ac50638bcece64b3b436d3a61b70ed6c01a34",
              "versionType": "git"
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            {
              "status": "affected",
              "version": "83d3bc866530a36a465b47cce4d2a9def2411960",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "6.6.113",
              "versionType": "semver"
            },
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              "status": "affected",
              "version": "6.12.54",
              "versionType": "semver"
            },
            {
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              "status": "affected",
              "version": "6.17.4",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/link.c",
            "fs/smb/client/smb1ops.c",
            "fs/smb/client/smb2ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "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": "6.6.160",
                  "versionStartIncluding": "6.6.113",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.12.54",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.17.4",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb/client: zero-initialize stack-allocated cifs_open_info_data\n\nStack-allocated cifs_open_info_data may contain random data.\nThis can make some fields have wrong value if they are not set later."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - smb_set_file_info, cifs_query_mf_symlink, and __cifs_sfu_make_node allocate cifs_open_info_data on the stack and pass it to open/query_path_info. Those run only from local VFS setattr (cifs_setattr_nounix), O_TMPFILE (set_tmpfile_attr), sfu mknod/symlink, and MF-symlink lookup (check_mf_symlink), not from ksmbd or demux-thread PDU parsing.\nAC:H - smb_set_file_info calls cifs_query_path_info, which walks uninitialized wsl.eas, only when the SMB1 session lacks CAP_NT_SMBS, and that walk runs only after the query sets reparse_point from ATTR_REPARSE_POINT. A local attacker cannot strip CAP_NT_SMBS or force that DOS attribute on a typical NT/SMB2/SMB3 server.\nPR:L - cifs_setattr_nounix \u2192 cifs_set_file_info needs only inode ownership or directory write (utimensat, chmod clearing ATTR_READONLY, O_TMPFILE via set_tmpfile_attr). CIFS is not FS_USERNS_MOUNT, but using an already-mounted share does not require init-namespace CAP_SYS_ADMIN.\nUI:N - The attacker issues setattr, mknod/symlink, or lookup themselves on a share that is already mounted (fstab/autofs/CIFS home). No separate victim mount or open is required at exploit time.\nS:U - The stack out-of-bounds walk/write in cifs_query_path_info stays inside the client kernel CIFS code and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - With ATTR_REPARSE_POINT set, cifs_query_path_info walks data-\u003ewsl.eas using leftover next_entry_offset with no bound against SMB2_WSL_MAX_QUERY_EA_RESP_SIZE, an unbounded out-of-bounds read of kernel stack and adjacent memory.\nI:H - After that walk, CIFSSMBQAllEAs writes $LXMOD/$LXDEV through the wild ea pointer and the code stores next_entry_offset/ea_name_length/ea_value_length at that location, a stack out-of-bounds write.\nA:H - The while (next) loop over uninitialized next_entry_offset can spin without bound or dereference unmapped memory and oops, hanging or crashing the setattr path."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:52:38.635Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2c5db82778f560121efda9e052e2f19c2d807c1b"
        },
        {
          "url": "https://git.kernel.org/stable/c/74ff47e6c4213fcfeba2de448d9cbda200507d22"
        },
        {
          "url": "https://git.kernel.org/stable/c/22532dd88694ed20bdd47523ffa709f166ce776b"
        },
        {
          "url": "https://git.kernel.org/stable/c/8fce4cf4369c766a3293a05419500cbfde72e60d"
        }
      ],
      "title": "smb/client: zero-initialize stack-allocated cifs_open_info_data",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93801",
    "datePublished": "2026-09-24T16:02:35.496Z",
    "dateReserved": "2026-09-18T17:59:28.789Z",
    "dateUpdated": "2026-10-21T12:52:38.635Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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