CVE-2026-93801 (GCVE-0-2026-93801)

Vulnerability from cvelistv5 – Published: 2026-09-24 16:02 – Updated: 2026-10-21 12:52
VLAI
Title
smb/client: zero-initialize stack-allocated cifs_open_info_data
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.
Severity
7 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6641 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 436cfdbc57d98808fce427d9a8d97691374989b3 , < 2c5db82778f560121efda9e052e2f19c2d807c1b (git)
Affected: fc2f2011d3d84b56f536b4a25a4bb2fa1b13d520 , < 74ff47e6c4213fcfeba2de448d9cbda200507d22 (git)
Affected: 057ac50638bcece64b3b436d3a61b70ed6c01a34 , < 22532dd88694ed20bdd47523ffa709f166ce776b (git)
Affected: 057ac50638bcece64b3b436d3a61b70ed6c01a34 , < 8fce4cf4369c766a3293a05419500cbfde72e60d (git)
Affected: 83d3bc866530a36a465b47cce4d2a9def2411960 (git)
Affected: 6.6.113 , < 6.6.160 (semver)
Affected: 6.12.54 , < 6.12.111 (semver)
Affected: 6.17.4 , < 6.18 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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      "cpeApplicability": [
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              "operator": "OR"
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          "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."
        }
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      "metrics": [
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            "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"
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        },
        {
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    "datePublished": "2026-09-24T16:02:35.496Z",
    "dateReserved": "2026-09-18T17:59:28.789Z",
    "dateUpdated": "2026-10-21T12:52:38.635Z",
    "state": "PUBLISHED"
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      "product_status:fixed": "1",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "smb/client: zero-initialize stack-allocated cifs_open_info_data",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-93801.json",
      "version": "2"
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            "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."
          }
        ],
        "id": "CVE-2026-93801",
        "lastModified": "2026-10-21T13:21:08.140",
        "metrics": {
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                "confidentialityImpact": "HIGH",
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      "product_status:known_affected": "110",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: smb/client: zero-initialize stack-allocated cifs_open_info_data",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93801.json",
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      "current_release_date": "2026-09-28T23:43:56Z",
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      "status": "interim",
      "title": "SUSE CVE CVE-2026-93801",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-93801.json",
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    }
  }
}



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