{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-31787",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-31787"
  ],
  "published": "2026-04-30T10:31:42Z",
  "summary": "xen/privcmd: fix double free via VMA splitting",
  "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",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.170",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-31787"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-06-15T02:03:26Z"
  }
}