{"id":"CVE-2026-63937","revision":"f56fa5e8f822440eb8974fcd2431d2a5","records":[{"revision":"f56fa5e8f822440eb8974fcd2431d2a5","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-63937","aliases":[],"title":"KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer","description":"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.","state":0,"publishedAt":"2026-07-19T14:55:34.554+00:00","modifiedAt":"2026-10-19T20:17:57.516+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/x86/kvm/svm/sev.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"9b54e248d2644be71cb394eb85f31ad99e023a05\",\n                            \"lessThan\": \"bd232801ef1d1fd985d2d4ca3cd1d888303ca86f\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9b54e248d2644be71cb394eb85f31ad99e023a05\",\n                            \"lessThan\": \"b1dfaa6f7a957726a6800135be3659fbe4bbf2a4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9b54e248d2644be71cb394eb85f31ad99e023a05\",\n                            \"lessThan\": \"edbbe88f83b524434974e84808d3093199d67c24\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9b54e248d2644be71cb394eb85f31ad99e023a05\",\n                            \"lessThan\": \"c8cc238093ca6c99267032f6cfe78f59389f3157\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/x86/kvm/svm/sev.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.11\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.11\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.93\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.35\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.12\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/bd232801ef1d1fd985d2d4ca3cd1d888303ca86f","https://git.kernel.org/stable/c/b1dfaa6f7a957726a6800135be3659fbe4bbf2a4","https://git.kernel.org/stable/c/edbbe88f83b524434974e84808d3093199d67c24","https://git.kernel.org/stable/c/c8cc238093ca6c99267032f6cfe78f59389f3157"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63937","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-63937","identifiers":["CVE-2026-63937"]},"retained":false,"historicalAffected":[]}],"coverage":[]}