{
  "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-2026-64181",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-64181",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-07-19T15:41:04.455Z",
    "updatedAt": "2026-08-05T12:39:56.626Z",
    "importedAt": "2026-10-24T01:58:25.636Z",
    "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": "mm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special()",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: fix __vm_normal_page() to handle missing support for pmd_special()/pud_special()\n\nOn x86 32-bit with THP enabled, zap_huge_pmd() is seen to generate a\n\"WARNING: mm/memory.c:735 at __vm_normal_page+0x6a/0x7d\", from the\nVM_WARN_ON_ONCE(is_zero_pfn(pfn) || is_huge_zero_pfn(pfn)); followed by\n\"BUG: Bad rss-counter state\"s, then later \"BUG: Bad page state\"s when\nreclaim gets to call shrink_huge_zero_folio_scan().\n\nIt's as if the _PAGE_SPECIAL bit never got set in the huge_zero pmd: and\nindeed, whereas pte_special() and pte_mkspecial() are subject to a\ndedicated CONFIG_ARCH_HAS_PTE_SPECIAL, pmd_special() and pmd_mkspecial()\nare subject to CONFIG_ARCH_SUPPORTS_PMD_PFNMAP, which is never enabled on\nany 32-bit architecture.\n\nWhile the problem was exposed through commit d80a9cb1a64a\n(\"mm/huge_memory: add and use normal_or_softleaf_folio_pmd()\"), it was an\noversight in commit af38538801c6 (\"mm/memory: factor out common code from\nvm_normal_page_*()\") and would result in other problems:\n* huge zero folio accounted in smaps, pagemap (PAGE_IS_FILE) and\n  numamaps as file-backed THP\n* folio_walk_start() returning the folio even without FW_ZEROPAGE set.\n  Callers seem to tolerate that, though.\n\n... and triggering the VM_WARN_ON_ONE(), although never reported so far.\n\nTo fix it, teach vm_normal_page_pmd()/vm_normal_page_pud() to consider\nwhether pmd_special/pud_special is actually implemented.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "af38538801c6a97565b44700ee6695d7d60ad779",
              "status": "affected",
              "versionType": "git",
              "lessThan": "62153767e8fc3889bc6508e9ffe927aaf64c4334"
            },
            {
              "version": "af38538801c6a97565b44700ee6695d7d60ad779",
              "status": "affected",
              "versionType": "git",
              "lessThan": "9052ea2ee2233be5d4786b8909151ca2bfbedf99"
            },
            {
              "version": "af38538801c6a97565b44700ee6695d7d60ad779",
              "status": "affected",
              "versionType": "git",
              "lessThan": "c0c6ccd9828c3a1950623b546fa57292a77b5c73"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "6.18",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "6.18"
            },
            {
              "version": "6.18.34",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "version": "7.0.11",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "7.0.*"
            },
            {
              "version": "7.1",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}