{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-53383",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-53383",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-07-19T11:59:31.616Z",
    "updatedAt": "2026-08-17T04:50:33.785Z",
    "importedAt": "2026-10-24T01:58:20.586Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "ksmbd: reject non-VALID session in compound request branch",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: reject non-VALID session in compound request branch\n\nsmb2_check_user_session() takes a shortcut for any operation that is not\nthe first in a COMPOUND request: it reuses work->sess (the session bound by\nthe first operation) and validates only the SessionId, then returns\n\"valid\". It never re-checks work->sess->state == SMB2_SESSION_VALID, and a\nSessionId of 0xFFFFFFFFFFFFFFFF (ULLONG_MAX, the MS-SMB2 related-operation\nvalue) skips even the id comparison. The standalone path\n(ksmbd_session_lookup_all() plus the SESSION_SETUP state machine) does\nenforce the VALID state; the compound branch bypasses all of it.\n\nA SESSION_SETUP carrying only an NTLM Type-1 (NtLmNegotiate) blob publishes\na fresh SMB2_SESSION_IN_PROGRESS session whose sess->user is still NULL\n(->user is assigned later, by ntlm_authenticate()). Used as operation 1 of\na COMPOUND with operation 2 = TREE_CONNECT (related, SessionId=ULLONG_MAX,\n\\\\host\\IPC$), the tree-connect then runs on that IN_PROGRESS session and\nreaches ksmbd_ipc_tree_connect_request(), which dereferences\nuser_name(sess->user) with sess->user == NULL (transport_ipc.c:687/701/704)\n-> remote NULL-pointer dereference and a kernel Oops that wedges the ksmbd\nworker for all clients.\n\nReject any non-first compound operation that lands on a session which is\nnot SMB2_SESSION_VALID, mirroring the validity the standalone lookup path\nenforces. SESSION_SETUP itself legitimately runs on an IN_PROGRESS session,\nbut it is never carried as a non-first compound operation, so multi-leg\nauthentication is unaffected by this check.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "eb947403518ea3d93f6d89264bb1f5416bb0c7d0",
              "status": "affected",
              "versionType": "git",
              "lessThan": "25ff12b82a376ff5c4583102a63d2456a6b9ebb9"
            },
            {
              "version": "854156d12caa9d36de1cf5f084591c7686cc8a9d",
              "status": "affected",
              "versionType": "git",
              "lessThan": "fc578523a72cb8b329d32070b95898e81613cc3f"
            },
            {
              "version": "5005bcb4219156f1bf7587b185080ec1da08518e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "d2bbbb6c55812220fee5d801c275cc267ea3cbeb"
            },
            {
              "version": "5005bcb4219156f1bf7587b185080ec1da08518e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "8f0302fb691537d33ec8f668565257ea9d340ffe"
            },
            {
              "version": "5005bcb4219156f1bf7587b185080ec1da08518e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "7cad3ceaf679c55bc9946685dacafce78ce6b51a"
            },
            {
              "version": "5005bcb4219156f1bf7587b185080ec1da08518e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "06e1f05a1dbe8bbd054c0927b17fc0a61cc8bef7"
            },
            {
              "version": "5005bcb4219156f1bf7587b185080ec1da08518e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "5f983b864d3d473ac533b2f4f44a1bbe5dcbccf4"
            },
            {
              "version": "5005bcb4219156f1bf7587b185080ec1da08518e",
              "status": "affected",
              "versionType": "git",
              "lessThan": "609ca17d869d04ba249e32cdcbf13c0b1c66f43c"
            },
            {
              "version": "d1066c1b3663401cd23c0d6e60cdae750ce00c0f",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "5.15.121",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "5.15.211"
            },
            {
              "version": "6.1.36",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.1.177"
            },
            {
              "version": "6.3.10",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.4"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "6.4",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "6.4"
            },
            {
              "version": "5.15.211",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.177",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.144",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.95",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.37",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "7.0.14",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.*"
            },
            {
              "version": "7.1.2",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "version": "7.2",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}