{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "9b54e248d2644be71cb394eb85f31ad99e023a05"
            },
            {
              "fixed": "bd232801ef1d1fd985d2d4ca3cd1d888303ca86f"
            },
            {
              "fixed": "b1dfaa6f7a957726a6800135be3659fbe4bbf2a4"
            },
            {
              "fixed": "edbbe88f83b524434974e84808d3093199d67c24"
            },
            {
              "fixed": "c8cc238093ca6c99267032f6cfe78f59389f3157"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.11.0"
            },
            {
              "fixed": "6.12.93"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.35"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63937.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer\n\nUse READ_ONCE() when reading entries/indices from the guest-accessible\nPage State Change buffer to defend against TOCTOU bugs.\n\nDon't bother with READ_ONCE()/WRITE_ONCE() for cases where KVM is writing\n(and not consuming the result!), as the guest isn't supposed to touch the\nbuffer while it's being processed.  I.e. using READ_ONCE() is all about\nprotecting against misbehaving guests.",
  "id": "CVE-2026-63937",
  "modified": "2026-07-22T05:30:02.399051115Z",
  "published": "2026-07-19T14:55:34.554Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b1dfaa6f7a957726a6800135be3659fbe4bbf2a4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bd232801ef1d1fd985d2d4ca3cd1d888303ca86f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c8cc238093ca6c99267032f6cfe78f59389f3157"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/edbbe88f83b524434974e84808d3093199d67c24"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63937.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63937"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer"
}