{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "f2b79c0d79683d552369bb9a7282c1f0226fc566"
            },
            {
              "fixed": "b96be860673f9fbbf12cdadb0b25fc4d6d4d207f"
            },
            {
              "fixed": "e163c7184acf36ac20a248498f4a16016057ca01"
            },
            {
              "fixed": "9c914b7a0bd18834505c65f22225ce22c152b2d9"
            },
            {
              "fixed": "7968852a7ca3ce81477ec5b4494a28d612f35a97"
            },
            {
              "fixed": "89a4ae32764172468dea303eb6ae90fe6c859712"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.6.0"
            },
            {
              "fixed": "6.6.157"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.110"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.51"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89961.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population\n\nvmemmap_populate_compound_pages() uses addr_pfn to determine the PFN\noffset within a compound page and to decide whether the current vmemmap\nslot should be populated as a head page mapping or should reuse a tail\npage mapping.\n\nHowever, addr_pfn is advanced manually in parallel with addr.  The loop\nitself progresses in vmemmap address space, so each PAGE_SIZE step in addr\ncovers PAGE_SIZE / sizeof(struct page) struct page slots.  Since addr_pfn\nis compared against nr_pages in data-PFN units, it should advance by the\nsame number of PFNs.  The existing manual increments do not match that and\ntherefore do not reliably track the PFN corresponding to the current addr.\n\nAs a result, pfn_offset can be computed from the wrong PFN and the code\ncan make the head/tail decision for the wrong compound-page position.\n\nFix this by deriving addr_pfn directly from the current vmemmap address\ninstead of carrying it as loop state.",
  "id": "CVE-2026-89961",
  "modified": "2026-09-18T03:30:40.327485776Z",
  "published": "2026-09-16T10:32:43.921Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7968852a7ca3ce81477ec5b4494a28d612f35a97"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/89a4ae32764172468dea303eb6ae90fe6c859712"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9c914b7a0bd18834505c65f22225ce22c152b2d9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b96be860673f9fbbf12cdadb0b25fc4d6d4d207f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e163c7184acf36ac20a248498f4a16016057ca01"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89961.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89961"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "powerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population"
}