{"id":"CVE-2026-63939","revision":null,"records":[{"revision":"4d56bb047d6d469188e02a725a451f9c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-63939","aliases":[],"title":"KVM: SEV: Compute the correct max length of the in-GHCB scratch area","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Compute the correct max length of the in-GHCB scratch area\n\nWhen setting the length of the GHCB scratch area, and the area is in the\nGHCB shared buffer, set the effective length of the scratch area to the max\npossible size given the start of the guest-provided pointer, and the end of\nthe shared buffer.\n\nThe code was \"fine\" when first introduced, as KVM doesn't consult the\nlength of the buffer when emulating MMIO, because the passed in @len always\nspecifies the *max* size required.  But for PSC requests, the incoming @len\nis just the minimum length (to process the header), and KVM needs to know\nthe full size of the scratch area to avoid buffer overflows (spoiler alert).\n\nOpportunistically rename @len => @min_len to better reflect its role.","state":0,"publishedAt":"2026-07-19T14:55:35.743+00:00","modifiedAt":"2026-10-19T20:17:57.791+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\": \"6ca9400d36005ffdca25f80186bea781c7e1dc4c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9b54e248d2644be71cb394eb85f31ad99e023a05\",\n                            \"lessThan\": \"9f0a9e780f02c02d025a190f1885e1d1d73b87bd\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9b54e248d2644be71cb394eb85f31ad99e023a05\",\n                            \"lessThan\": \"6644565527c4c5f507088b1c9ddf72de47790b68\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9b54e248d2644be71cb394eb85f31ad99e023a05\",\n                            \"lessThan\": \"5867d7e202e09f037cefe77f7af4413c7c0fa088\",\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:N/UI:N/S:C/C:H/I:H/A:H","score":9.3,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/6ca9400d36005ffdca25f80186bea781c7e1dc4c","https://git.kernel.org/stable/c/9f0a9e780f02c02d025a190f1885e1d1d73b87bd","https://git.kernel.org/stable/c/6644565527c4c5f507088b1c9ddf72de47790b68","https://git.kernel.org/stable/c/5867d7e202e09f037cefe77f7af4413c7c0fa088"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63939","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-63939","identifiers":["CVE-2026-63939"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-db1b57b5c8cf41498e207884b3f1235b","complete":true,"records":13654,"lastAttemptAt":"2026-11-08T18:47:45.2749951+00:00","lastSuccessAt":"2026-11-08T17:47:46.718+00:00","error":null,"lastVerifiedAt":"2026-11-08T17:47:46.718+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-08T18:47:41.4173610+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-08T18:47:41.417361+00:00","lastSuccessAt":"2026-11-08T18:47:41.7296264+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.7296273+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-16991eac9aa5423ca0d0a0955fbb9b20","complete":true,"records":13666,"lastAttemptAt":"2026-11-08T18:47:44.4093775+00:00","lastSuccessAt":"2026-11-08T17:47:45.702+00:00","error":null,"lastVerifiedAt":"2026-11-08T17:47:45.702+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13706,"expectedIdentifiers":13706,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-980593e6977a6d1b4fb1eed5a1ffe88a468736f89f0a06f710924ad59132c023","complete":true,"records":9914,"lastAttemptAt":"2026-11-08T18:47:41.2273184+00:00","lastSuccessAt":"2026-11-08T11:07:07.068788+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.2273184+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-08T18:47:41.0199708+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.0199708+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-964c14035e6f0f6478b2870fad6a7ef9f6045876d4a12af2c2e514521e54b6af","complete":true,"records":3055,"lastAttemptAt":"2026-11-08T18:47:41.3406936+00:00","lastSuccessAt":"2026-11-08T11:07:12.1927025+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.3406936+00:00","snapshotPublishedAt":"2026-11-08T11:02:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-f8647d7ba64b1ba0dfdc7130944766d5b36d5b77d18fff0c79e651a4cff3c2b9","complete":true,"records":231293,"lastAttemptAt":"2026-11-08T18:47:41.1240385+00:00","lastSuccessAt":"2026-11-08T11:06:56.2918717+00:00","error":null,"lastVerifiedAt":"2026-11-08T18:47:41.1240385+00:00","snapshotPublishedAt":"2026-11-08T11:02:50+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}