{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "df7a6d1f64056aec572162c5d35ed9ff86ece6f3"
            },
            {
              "fixed": "b0b1b9ca80b795ed2223e76dd787db7067121fb9"
            },
            {
              "fixed": "a3c65af20cceb7f997847727636b4017326f845d"
            },
            {
              "fixed": "0f001491e5a2ec69aa9d5dd6b799e5742245f9ea"
            },
            {
              "fixed": "5120b1e048d48596ffaec1a8412012a91adba73b"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.9.0"
            },
            {
              "fixed": "6.12.110"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.50"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89593.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nhugetlb: only adjust reservation during unmapping if mapcount is 0\n\nSince df7a6d1f6405, __unmap_hugepage_range can adjust reservations.  In\nthe case of folio mapped in both a parent and a child, if the parent\nunmaps the range first, the reservation adjustment will result in an\nunderflow of the reserved count.  Once the child unmaps the range, the\ncount is restored.  Change __unmap_hugepage_range() to check the mapcount\nbefore adjusting the reservation.",
  "id": "CVE-2026-89593",
  "modified": "2026-09-15T03:30:52.942658626Z",
  "published": "2026-09-11T19:44:56.557Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0f001491e5a2ec69aa9d5dd6b799e5742245f9ea"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5120b1e048d48596ffaec1a8412012a91adba73b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a3c65af20cceb7f997847727636b4017326f845d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b0b1b9ca80b795ed2223e76dd787db7067121fb9"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89593.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89593"
    },
    {
      "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:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "hugetlb: only adjust reservation during unmapping if mapcount is 0"
}