{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "d71f513985c22f1050295d1a7e4327cf9fb060da"
            },
            {
              "fixed": "dbf862ce9f009128ab86b234d91413a3e450beb4"
            },
            {
              "fixed": "2b985d3a024b9e8c24e21671b34e855569763808"
            },
            {
              "fixed": "1576ff3869cbd3620717195f971c85b7d7fd62b5"
            },
            {
              "fixed": "402d84ad9e89bd4cbfd07ca8598532b7021daf95"
            },
            {
              "fixed": "2894a351fe2ea8684919d36df3188b9a35e3926f"
            },
            {
              "fixed": "446ee446d9ae66f36e95c3c90bbcc4e56b94cde0"
            },
            {
              "fixed": "71bf829800758a6e3889096e4754ef47ba7fc850"
            },
            {
              "fixed": "24daca4fc07f3ff8cd0e3f629cd982187f48436a"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.8.0"
            },
            {
              "fixed": "5.10.254"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.204"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.170"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.137"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.85"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.26"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31787.json"
  },
  "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": "CVE-2026-31787",
  "modified": "2026-07-08T05:37:59.437798746Z",
  "published": "2026-04-30T10:31:28.992Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/04/28/14"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1576ff3869cbd3620717195f971c85b7d7fd62b5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/24daca4fc07f3ff8cd0e3f629cd982187f48436a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2894a351fe2ea8684919d36df3188b9a35e3926f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b985d3a024b9e8c24e21671b34e855569763808"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/402d84ad9e89bd4cbfd07ca8598532b7021daf95"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/446ee446d9ae66f36e95c3c90bbcc4e56b94cde0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/71bf829800758a6e3889096e4754ef47ba7fc850"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dbf862ce9f009128ab86b234d91413a3e450beb4"
    },
    {
      "type": "ADVISORY",
      "url": "http://xenbits.xen.org/xsa/advisory-487.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31787.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31787"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "summary": "xen/privcmd: fix double free via VMA splitting"
}