{
  "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-2026-31669",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-31669",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-04-24T14:45:17.295Z",
    "updatedAt": "2026-10-19T18:56:03.360Z",
    "importedAt": "2026-10-24T01:58:02.025Z",
    "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": "mptcp: fix slab-use-after-free in __inet_lookup_established",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix slab-use-after-free in __inet_lookup_established\n\nThe ehash table lookups are lockless and rely on\nSLAB_TYPESAFE_BY_RCU to guarantee socket memory stability\nduring RCU read-side critical sections. Both tcp_prot and\ntcpv6_prot have their slab caches created with this flag\nvia proto_register().\n\nHowever, MPTCP's mptcp_subflow_init() copies tcpv6_prot into\ntcpv6_prot_override during inet_init() (fs_initcall, level 5),\nbefore inet6_init() (module_init/device_initcall, level 6) has\ncalled proto_register(&tcpv6_prot). At that point,\ntcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab\nremains NULL permanently.\n\nThis causes MPTCP v6 subflow child sockets to be allocated via\nkmalloc (falling into kmalloc-4k) instead of the TCPv6 slab\ncache. The kmalloc-4k cache lacks SLAB_TYPESAFE_BY_RCU, so\nwhen these sockets are freed without SOCK_RCU_FREE (which is\ncleared for child sockets by design), the memory can be\nimmediately reused. Concurrent ehash lookups under\nrcu_read_lock can then access freed memory, triggering a\nslab-use-after-free in __inet_lookup_established.\n\nFix this by splitting the IPv6-specific initialization out of\nmptcp_subflow_init() into a new mptcp_subflow_v6_init(), called\nfrom mptcp_proto_v6_init() before protocol registration. This\nensures tcpv6_prot_override.slab correctly inherits the\nSLAB_TYPESAFE_BY_RCU slab cache.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
              "status": "affected",
              "versionType": "git",
              "lessThan": "f6e1f25fa5e733570f6d6fe37a4dfed2a0deba47"
            },
            {
              "version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
              "status": "affected",
              "versionType": "git",
              "lessThan": "fb1f54b7d16f393b8b65d328410f78b4beea8fcc"
            },
            {
              "version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
              "status": "affected",
              "versionType": "git",
              "lessThan": "3fd6547f5b8ac99687be6d937a0321efda760597"
            },
            {
              "version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
              "status": "affected",
              "versionType": "git",
              "lessThan": "eb9c6aeb512f877cf397deb1e4526f646c70e4a7"
            },
            {
              "version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
              "status": "affected",
              "versionType": "git",
              "lessThan": "15fa9ead4d5e6b6b9c794e84144146c917f2cb62"
            },
            {
              "version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
              "status": "affected",
              "versionType": "git",
              "lessThan": "b313e9037d98c13938740e5ebda7852929366dff"
            },
            {
              "version": "b19bc2945b40b9fd38e835700907ffe8534ef0de",
              "status": "affected",
              "versionType": "git",
              "lessThan": "9b55b253907e7431210483519c5ad711a37dafa1"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "5.12",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "5.12"
            },
            {
              "version": "5.15.203",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "version": "6.1.169",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "version": "6.6.135",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "version": "6.12.82",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "version": "6.18.23",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "6.19.13",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "version": "7.0",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}