{"id":"CVE-2026-98718","state":"PUBLISHED","title":"KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state\n\nExplicitly flush caches after intra-host migration before clearing \"SEV\nactive\" on the source VM, as doing cache maintenance afterwards creates a\ntiny window where memory reclaim could return memory to the host without\nperforming a cache flush, e.g. as pointed out by Sashiko:\n\n  CPU1 in sev_migrate_from():\n    src->active = false;\n\n  CPU2 running concurrent unmap:\n    Since active is false, the automatic cache flush in\n    sev_guest_memory_reclaimed is skipped.\n    The host frees and reallocates the page.\n\n  CPU1 in sev_migrate_from():\n    sev_writeback_caches(src_kvm);\n    Executes a hardware cache flush (wbnoinvd), which writes the guest's old\n    dirty ciphertext over the new page owner's data.","publishedAt":"2026-10-18T15:46:53.611Z","updatedAt":"2026-10-19T09:24:29.156Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"37dfb676fafd1eef36fe0bb649607afbb0d5521b","status":"affected","lessThan":"8b7d4f68fef96cebe0b6dbb6e5607772337f7369","versionType":"git"},{"version":"d4cc2dff12116a700add601c0262132cc26e1b2c","status":"affected","lessThan":"de83ff6a4d8f3618473bedb3c4400020c22e8a8a","versionType":"git"},{"version":"93de2a6a4b91b72607136dd656edf03fb399d27f","status":"affected","lessThan":"973ea70393e885e540f714904e51bc6cac80e3d7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kvm/svm/sev.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.18.55","status":"affected","lessThan":"6.18.56","versionType":"semver"},{"version":"7.2.9","status":"affected","lessThan":"7.2.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kvm/svm/sev.c"]}],"references":["https://git.kernel.org/stable/c/8b7d4f68fef96cebe0b6dbb6e5607772337f7369","https://git.kernel.org/stable/c/de83ff6a4d8f3618473bedb3c4400020c22e8a8a","https://git.kernel.org/stable/c/973ea70393e885e540f714904e51bc6cac80e3d7"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98718.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98718","state":"PUBLISHED","datePublished":"2026-10-18T15:46:53.611Z","dateUpdated":"2026-10-19T09:24:29.156Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.366Z"},"containers":{"cna":{"title":"KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state\n\nExplicitly flush caches after intra-host migration before clearing \"SEV\nactive\" on the source VM, as doing cache maintenance afterwards creates a\ntiny window where memory reclaim could return memory to the host without\nperforming a cache flush, e.g. as pointed out by Sashiko:\n\n  CPU1 in sev_migrate_from():\n    src->active = false;\n\n  CPU2 running concurrent unmap:\n    Since active is false, the automatic cache flush in\n    sev_guest_memory_reclaimed is skipped.\n    The host frees and reallocates the page.\n\n  CPU1 in sev_migrate_from():\n    sev_writeback_caches(src_kvm);\n    Executes a hardware cache flush (wbnoinvd), which writes the guest's old\n    dirty ciphertext over the new page owner's data."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"37dfb676fafd1eef36fe0bb649607afbb0d5521b","status":"affected","lessThan":"8b7d4f68fef96cebe0b6dbb6e5607772337f7369","versionType":"git"},{"version":"d4cc2dff12116a700add601c0262132cc26e1b2c","status":"affected","lessThan":"de83ff6a4d8f3618473bedb3c4400020c22e8a8a","versionType":"git"},{"version":"93de2a6a4b91b72607136dd656edf03fb399d27f","status":"affected","lessThan":"973ea70393e885e540f714904e51bc6cac80e3d7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kvm/svm/sev.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.18.55","status":"affected","lessThan":"6.18.56","versionType":"semver"},{"version":"7.2.9","status":"affected","lessThan":"7.2.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kvm/svm/sev.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/8b7d4f68fef96cebe0b6dbb6e5607772337f7369"},{"url":"https://git.kernel.org/stable/c/de83ff6a4d8f3618473bedb3c4400020c22e8a8a"},{"url":"https://git.kernel.org/stable/c/973ea70393e885e540f714904e51bc6cac80e3d7"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:24:29.156Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.55","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.2.9","versionEndExcluding":"7.2.10"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}