{
  "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-2026-98983",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-98983",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-10-23T12:20:00.918Z",
    "updatedAt": "2026-10-23T12:20:00.918Z",
    "importedAt": "2026-10-24T01:58:41.756Z",
    "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": "unshare: don't drop active namespace references that were never taken",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nunshare: don't drop active namespace references that were never taken\n\nActive references on the namespaces of an nsproxy are taken when the\nnsproxy is installed into a task in switch_task_namespaces() and\ncopy_namespaces() and dropped again by put_nsproxy() through\ndeactivate_nsproxy().\n\nBut ksys_unshare() calls put_nsproxy() on an nsproxy that was never\ninstalled when set_cred_ucounts() fails. The new namespaces of that\nnsproxy go from zero to minus one and the namespaces shared with the\ncaller lose a reference that belongs to the nsproxy the caller keeps\nusing:\n\n  WARNING: kernel/nscommon.c:171 at __ns_ref_active_put+0x1cd/0x230\n   nsproxy_ns_active_put\n   deactivate_nsproxy\n   ksys_unshare\n\nAfterwards the namespaces the caller lives in aren't listed by listns()\nanymore. set_cred_ucounts() only fails when alloc_ucounts() can't\nallocate and it only allocates when the real uid of the caller differs\nfrom its effective uid.\n\nCommit cefd55bd2159 (\"nsproxy: fix free_nsproxy() and simplify\ncreate_new_namespaces()\") separated the two cases on purpose.\nnsproxy_free() frees an nsproxy that was prepared but never installed\nand that's what a failed setns() uses in put_nsset(). Export it and use\nit for a failed unshare() as well.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "a98621a0f187a934c115dcfe79a49520ae892111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "56fe03a0c05dba4c5f6a23c391f96de1614a098c"
            },
            {
              "version": "a98621a0f187a934c115dcfe79a49520ae892111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "0b6f31a3c0b16066f812e94b52a704174a6f23cd"
            },
            {
              "version": "27ae6b17c9ba7ff353ab0906297f08aa845782b4",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "297261b343371c4f0b31055d53d285138ec21565",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "813a47b0309097da71781ee4ac11922e39b67d55",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "6e608e3e5ce12ce7fd21e46212eccca37f917d0e",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "a261fccdb4ac58ec5ba6aa1d92a6cc418fff301f",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "665dc1ed16357988d439fc5bbc860ee36f540d81",
              "status": "affected",
              "versionType": "git"
            },
            {
              "version": "5.15.209",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "5.16"
            },
            {
              "version": "6.1.175",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.2"
            },
            {
              "version": "6.6.141",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.7"
            },
            {
              "version": "6.12.91",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.13"
            },
            {
              "version": "6.18.33",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "6.19"
            },
            {
              "version": "7.0.10",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "7.1"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "7.1",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "7.1"
            },
            {
              "version": "7.2.11",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "version": "7.3",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}