{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "41d88484c71cd4f659348da41b7b5b3dbd3be1f6"
            },
            {
              "fixed": "591b6fac9df3f43522e8ff6eed8662f8b6f1a124"
            },
            {
              "fixed": "fb97d1d6c20692e15247fa5c8b894b2325e38aee"
            },
            {
              "fixed": "1aac65f3e651334259ecb2a5f5ddb81c01f02599"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.15.0"
            },
            {
              "fixed": "6.18.52"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93066.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm/pat: Take cpa_lock around large-page collapse\n\nLoading and unloading modules concurrently on several CPUs on a KASAN\nbuild, with a short delay injected at the CPA page-table lookup to\nwiden the window, faults within minutes:\n\n  BUG: KASAN: use-after-free in __change_page_attr+0x7cc/0x7e0\n  Write of size 8 at addr ffff888181139718 by task modprobe\n  ...\n  The buggy address belongs to the physical page:\n   pfn:0x181139 ... page_type: f2(table)\n\ncpa_collapse_large_pages() rebuilds a leaf PMD from its 4K PTEs and\nfrees the old PTE-table pages, while __change_page_attr() fetches a\nPTE pointer from a lockless lookup_address_in_pgd_attr() and writes\nit with set_pte_atomic() only later. When module text is served from\na shared large ROX mapping the two run on the same PMD:\n\n  CPU A (module load)              CPU B (module finalize)\n  -------------------              -----------------------\n  execmem_make_temp_rw\n   set_memory_nx\n    __change_page_attr\n     split 2M -\u003e 4K table P\n     kpte = \u0026P[i]  (lockless)\n                                   execmem_restore_rox\n                                    set_memory_rox (CPA_COLLAPSE)\n                                     cpa_collapse_large_pages\n                                      rebuild leaf PMD\n                                      flush_tlb_all\n                                      pagetable_free(P)\n     set_pte_atomic(kpte, ...)\n       -\u003e writes into freed P\n\nP is a page-table page (page_type: table), reused at once, so the\nwrite corrupts whatever got the page next: a bad-pte or bad-page\nsplat, or a fatal fault once P has been turned into read-only text.\n\nThe flush_tlb_all() before the free does not close this: its IPI only\nserializes against page-table walkers that run with interrupts off\n(e.g. GUP-fast); the walk in __change_page_attr() runs with interrupts\non, so nothing stops it from holding a stale pointer into P.\n\nSerialize the collapse - the PMD rebuild, TLB flush and PTE-table\nfree - under cpa_lock, the same lock __change_page_attr() now takes\nunconditionally since commit (\"x86/mm/pat: stop gating cpa_lock on\ndebug_pagealloc_enabled()\"), so a concurrent walker can no longer\nhold a pointer into a table the collapse is about to free.",
  "id": "CVE-2026-93066",
  "modified": "2026-09-19T03:30:25.664356286Z",
  "published": "2026-09-17T16:10:51.612Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1aac65f3e651334259ecb2a5f5ddb81c01f02599"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/591b6fac9df3f43522e8ff6eed8662f8b6f1a124"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fb97d1d6c20692e15247fa5c8b894b2325e38aee"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93066.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93066"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "x86/mm/pat: Take cpa_lock around large-page collapse"
}