{"id":"CVE-2026-98472","kind":"vulnerability","aliases":["CVE-2026-98472"],"related":[],"title":"Linux kernel KVM: SEV VM destroy path leaks a CPU mask","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Free have_run_cpus during VM destruction even if VM is no longer SEV\n\nUnconditionally free SEV's \"have run CPUs\" cpumask in the VM destroy path,\ni.e. even for what appear to be non-SEV VMs, as an SEV VM becomes a non-SEV\nVM if its state is intra-host migrated.  Alternatively, the mask could be\nfreed in sev_migrate_from() when \"converting\" the source VM, but that gets\nannoying because ideally KVM would nullify the mask to guard against UAF,\nand nullifying the mask would need be conditioned on CPUMASK_OFFSTACK=y.\n\nFreeing the mask during sev_migrate_from() is also not robust against other\nKVM bugs, though that's kind of a moot point since any such bugs would show\nup even if sev->active is never set.  I.e. KVM must get that side of things\ncorrect.  But, that's not a great reason to add more code just to make\nthings marginally less robust.","summary":"In the Linux KVM SEV code, the \"have run CPUs\" cpumask is not freed during VM destruction when an SEV VM has been converted to a non-SEV VM by intra-host migration. The sources describe a resource leak and do not state a confirmed attacker capability.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["kvm","linux-kernel","runtime","self-hosted","sev"],"not_affected_if":["no-kvm","no-sev-guests"],"how_to_check":"- unknown","fix":"- Update the Linux kernel to a release that includes the upstream fix for KVM: SEV have_run_cpus freeing (version unknown from the sources)","status":"open","published_at":"2026-10-18T16:16:57+00:00","first_seen_at":"2026-10-23T21:57:15+00:00","triaged_at":"2026-10-25T05:26:00+00:00","updated_at":"2026-10-25T05:26:00+00:00","category":"runtime","confidence":0.4,"triage":{"at":"2026-10-25T05:26:00Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a release that includes the upstream fix for KVM: SEV have_run_cpus freeing (version unknown from the sources)","reach":"local","title":"Linux kernel KVM: SEV VM destroy path leaks a CPU mask","impact":"low","summary":"In the Linux KVM SEV code, the \"have run CPUs\" cpumask is not freed during VM destruction when an SEV VM has been converted to a non-SEV VM by intra-host migration. The sources describe a resource leak and do not state a confirmed attacker capability.","category":"runtime","nicknames":[],"who_cares":["linux-kernel","kvm","sev","self-hosted"],"confidence":0.4,"needs_auth":"unknown","worst_case":"unknown; the sources describe a memory leak, not a confirmed escalation","analyst_note":"Check the upstream kernel commit and NVD entry for CVE-2026-98472 to confirm the impact and fixed kernel versions.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-kvm","no-sev-guests"],"who_is_affected":"Hosts running Linux with KVM hypervisor support that run SEV or SEV-ES guests and perform intra-host migration of those guests. Hosts without KVM SEV guests are unlikely to be affected. The sources do not give further detail.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000614,"input_tokens":3563,"output_tokens":515,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-98472':14A,17A 'activ':219C 'add':240C 'also':194C 'altern':144C 'annoy':162C 'appear':119C 'attack':74B 'becom':130C 'bug':200C,212C 'capabl':75B 'code':32B,242C 'condit':181C 'confirm':73B 'convert':50B,155C 'correct':231C 'could':147C 'cpu':10A 'cpumask':37B,109C,183C 'cpus':36B,91C,108C 'cve':12A,15A 'describ':64B 'destroy':6A,113C 'destruct':43B,94C 'even':95C,116C,216C 'follow':81C 'free':88C,103C,186C 'freed':40B,149C 'get':161C,226C 'great':237C 'guard':171C 'host':25B,60B,142C 'i.e':115C,223C 'ideal':164C 'intra':59B,141C 'intra-host':58B,140C 'kernel':2A,21B,79C 'kind':204C 'kvm':3A,18B,30B,86C,165C,199C,224C 'leak':8A,67B 'less':248C 'linux':1A,20B,29B,78C 'linux-kernel':19B 'longer':100C 'make':245C 'margin':247C 'mask':11A,146C,169C,177C,188C 'migrat':61B,143C,152C,191C 'moot':207C 'must':225C 'need':179C 'never':221C 'non':54B,123C,133C 'non-sev':53B,122C,132C 'nullifi':167C,175C 'offstack':184C 'path':7A,114C 'point':208C 'reason':238C 'resolv':85C 'resourc':66B 'robust':196C,249C 'run':35B,90C,107C 'runtim':22B 'self':24B 'self-host':23B 'set':222C 'sev':4A,26B,31B,46B,55B,87C,101C,104C,124C,128C,134C,151C,190C,218C 'show':214C 'side':228C 'sinc':209C 'sourc':63B,157C 'state':71B,138C 'thing':230C,246C 'though':201C 'uaf':173C 'uncondit':102C 'vm':5A,42B,47B,56B,93C,97C,112C,129C,135C,158C 'vms':125C 'vulner':82C 'would':166C,178C,213C 'y':185C","nicknames":[],"mitigations":[],"who_affected":"Hosts running Linux with KVM hypervisor support that run SEV or SEV-ES guests and perform intra-host migration of those guests. Hosts without KVM SEV guests are unlikely to be affected. The sources do not give further detail.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:16:57+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98472","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98472","severity":null,"published_at":"2026-10-18T16:16:57+00:00","modified_at":"2026-10-19T10:18:57+00:00","first_seen_at":"2026-10-23T21:57:15+00:00","fetched_at":"2026-10-23T22:28:56+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}