{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.21",
        "name": "xen",
        "purl": "pkg:apk/alpine/xen?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.22",
        "name": "xen",
        "purl": "pkg:apk/alpine/xen?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.23",
        "name": "xen",
        "purl": "pkg:apk/alpine/xen?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxen/privcmd: fix double free via VMA splitting\n\nprivcmd_vm_ops defines .close (privcmd_close), but neither .may_split\nnor .open. When userspace does a partial munmap() on a privcmd mapping,\nthe kernel splits the VMA via __split_vma(). Since may_split is NULL,\nthe split is allowed. vm_area_dup() copies vm_private_data (a pages\narray allocated in alloc_empty_pages()) into the new VMA without any\nfixup, because there is no .open callback.\n\nBoth VMAs now point to the same pages array. When the unmapped portion\nis closed, privcmd_close() calls:\n    - xen_unmap_domain_gfn_range()\n    - xen_free_unpopulated_pages()\n    - kvfree(pages)\n\nThe surviving VMA still holds the dangling pointer. When it is later\ndestroyed, the same sequence runs again, which leads to a double free.\n\nFix this issue by adding a .may_split callback denying the VMA split.\n\nThis is XSA-487 / CVE-2026-31787",
  "id": "ALPINE-CVE-2026-31787",
  "modified": "2026-05-01T08:18:04.897050470Z",
  "published": "2026-04-30T11:16:21.087Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security.alpinelinux.org/vuln/CVE-2026-31787"
    }
  ],
  "upstream": [
    "CVE-2026-31787"
  ]
}