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

Vulnerability from cvelistv5 – Published: 2026-09-24 16:02 – Updated: 2026-09-25 12:43
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
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: fc2f2011d3d84b56f536b4a25a4bb2fa1b13d520 , < 74ff47e6c4213fcfeba2de448d9cbda200507d22 (git)
Affected: 057ac50638bcece64b3b436d3a61b70ed6c01a34 , < 22532dd88694ed20bdd47523ffa709f166ce776b (git)
Affected: 057ac50638bcece64b3b436d3a61b70ed6c01a34 , < 8fce4cf4369c766a3293a05419500cbfde72e60d (git)
Affected: 436cfdbc57d98808fce427d9a8d97691374989b3 (git)
Affected: 83d3bc866530a36a465b47cce4d2a9def2411960 (git)
Affected: 6.12.54 , < 6.12.111 (semver)
Affected: 6.6.113 , < 6.7 (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: 6.12.111 , ≤ 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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/link.c",
            "fs/smb/client/smb1ops.c",
            "fs/smb/client/smb2ops.c"
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              "versionType": "git"
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              "versionType": "git"
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              "versionType": "git"
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              "status": "affected",
              "version": "6.12.54",
              "versionType": "semver"
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              "version": "6.6.113",
              "versionType": "semver"
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              "status": "affected",
              "version": "6.17.4",
              "versionType": "semver"
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          "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": "6.18"
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              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.12.54",
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              "operator": "OR"
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      "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": "2026-09-25T12:43:08.420Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "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"
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93801",
    "datePublished": "2026-09-24T16:02:35.496Z",
    "dateReserved": "2026-09-18T17:59:28.789Z",
    "dateUpdated": "2026-09-25T12:43:08.420Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-25",
      "epss": "0.0012",
      "percentile": "0.01626"
    },
    "nvd": {
      "cve": {
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                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/client/link.c",
                  "fs/smb/client/smb1ops.c",
                  "fs/smb/client/smb2ops.c"
                ],
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                "product": "Linux",
                "programFiles": [
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                  "fs/smb/client/smb2ops.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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                    "version": "6.18.53",
                    "versionType": "semver"
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        ],
        "cveTags": [],
        "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."
          }
        ],
        "id": "CVE-2026-93801",
        "lastModified": "2026-09-25T13:17:20.957",
        "metrics": {
          "cvssMetricV31": [
            {
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                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.0,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.0,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-24T17:17:13.017",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/22532dd88694ed20bdd47523ffa709f166ce776b"
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          }
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-09-24T23:47:34Z",
      "cve": "CVE-2026-93801",
      "id": "CVE-2026-93801",
      "initial_release_date": "2026-09-24T23:47:34Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-93801",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-93801.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.