{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "84b7625728ea311ea35bdaa0eded53c1c56baeaa"
            },
            {
              "fixed": "e3af585e1728c917682b6a3de9a69b41fb9194d4"
            },
            {
              "fixed": "8288d031a01dbacfde3fc643f7be3d23504de64d"
            },
            {
              "fixed": "f458ba102da97fafca106327086fc95f3fc764cb"
            },
            {
              "fixed": "4b4defd2fce3f966c25adabf46644a85558f1169"
            },
            {
              "fixed": "5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a"
            },
            {
              "fixed": "d5f59216650c51e5e3fcb7517c825bc8047f60ef"
            },
            {
              "fixed": "52cecff98bda2c51eed1c6ce9d21c5d6268fb19d"
            },
            {
              "fixed": "27fdbab4221b375de54bf91919798d88520c6e28"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.13.0"
            },
            {
              "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-2026-31786.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBuffer overflow in drivers/xen/sys-hypervisor.c\n\nThe build id returned by HYPERVISOR_xen_version(XENVER_build_id) is\nneither NUL terminated nor a string.\n\nThe first causes a buffer overflow as sprintf in buildid_show will\nread and copy till it finds a NUL.\n\n00000000  f4 91 51 f4 dd 38 9e 9d  65 47 52 eb 10 71 db 50  |..Q..8..eGR..q.P|\n00000010  b9 a8 01 42 6f 2e 32                              |...Bo.2|\n00000017\n\nSo use a memcpy instead of sprintf to have the correct value:\n\n00000000  f4 91 51 f4 dd 00 9e 9d  65 47 52 eb 10 71 db 50  |..Q.....eGR..q.P|\n00000010  b9 a8 01 42                                       |...B|\n00000014\n\n(the above have a hack to embed a zero inside and check it's\nreturned correctly).\n\nThis is XSA-485 / CVE-2026-31786",
  "id": "CVE-2026-31786",
  "modified": "2026-07-08T05:37:35.240072524Z",
  "published": "2026-04-30T10:31:28.293Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/04/28/12"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/27fdbab4221b375de54bf91919798d88520c6e28"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b4defd2fce3f966c25adabf46644a85558f1169"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/52cecff98bda2c51eed1c6ce9d21c5d6268fb19d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5c5ff7c7bd15bb536f44b10b3fb5b8408f344d0a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8288d031a01dbacfde3fc643f7be3d23504de64d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d5f59216650c51e5e3fcb7517c825bc8047f60ef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e3af585e1728c917682b6a3de9a69b41fb9194d4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f458ba102da97fafca106327086fc95f3fc764cb"
    },
    {
      "type": "ADVISORY",
      "url": "http://xenbits.xen.org/xsa/advisory-485.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31786.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31786"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "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": "Buffer overflow in drivers/xen/sys-hypervisor.c"
}