{
  "cveId": "CVE-2026-72043",
  "url": "https://patchblox.com/security/cve/CVE-2026-72043",
  "summary": "CVE-2026-72043 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-72043, released August 15, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  LoongArch: Fix missing dirty page tracking in {p...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  LoongArch: Fix missing dirty page tracking in {pte,pmd}_wrprotect()  When hardware page table walker (PTW) is enabled on LoongArch, the CPU may set _PAGE_DIRTY directly in the page table entry during a write TLB miss, without going through the software TLB store handler. The software TLB store handler (tlbex.S:254) sets both _PAGE_DIRTY and_PAGE_MODIFIED together:      ori t0, t0, (_PAGE_VALID | _PAGE_DIRTY | _PAGE_MODIFIED)  Since hardware PTW only sets _PAGE_DIRTY, the software-only bit, i.e. _PAGE_MODIFIED is left unchanged. This creates a window where a PTE has _PAGE_DIRTY set (hardware knows the page is dirty) but _PAGE_MODIFIED clear (software is unaware).  When fork()/clone() triggers copy-on-write, __copy_present_ptes() calls pte_wrprotect(), which unconditionally clears both the _PAGE_WRITE and _PAGE_DIRTY bits:      pte_val(pte) \u0026= ~(_PAGE_WRITE | _PAGE_DIRTY);  Since _PAGE_MODIFIED was never set, the dirtiness information is lost completely. Subsequently, when memory pressure triggers page reclaim, page_mkclean() / try_to_unmap() sees the page as clean (i.e. pte_dirty() returns false) and the page may be freed without writeback, causing data corruption.  Fix this by propagating the _PAGE_DIRTY bit to the _PAGE_MODIFIED bit in both pte_wrprotect() and pmd_wrprotect() before clearing writeable bits:      if (pte_val(pte) \u0026 _PAGE_DIRTY)         pte_val(pte) |= _PAGE_MODIFIED;  The pmd_wrprotect() fix handles the CONFIG_TRANSPARENT_HUGEPAGE case, where pmd entries need the same treatment.  This ensures the software dirty tracking bit (checked by pte_dirty() and pmd_dirty(), which read both the _PAGE_DIRTY and _PAGE_MODIFIED bits) is preserved across fork COW write-protection.  The issue was found by the LTP madvise09 test case, which exercises page reclaim after \u0022madvise(MADV_FREE), write and fork\u0022 operation sequence on private anonymous mappings.",
  "published": "2026-08-15T06:21:13Z",
  "severity": "high",
  "cvss": 7.1,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
  "epss": 0.00172,
  "epssPercentile": 0.06643,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.1.180-1",
      "fix": "DEBIAN-CVE-2026-72043",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-72043",
      "released": "2026-08-15T22:38:55Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.100-1",
      "fix": "DEBIAN-CVE-2026-72043",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-72043",
      "released": "2026-08-15T22:38:55Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.1.5-1",
      "fix": "DEBIAN-CVE-2026-72043",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-72043",
      "released": "2026-08-15T22:38:55Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}