{"id":"CVE-2026-98466","kind":"vulnerability","aliases":["CVE-2026-98466"],"related":[],"title":"Linux kernel KVM arm64: hypervisor stack pages left mapped to host","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Transfer the hyp stack pages out of the host stage-2\n\nfix_host_ownership() walks only the linear-map alias of each memblock\nregion, and the per-CPU hyp stack, mapped in the private VA range for\nits guard page, has none.\n\nWalk each stack's VA range with the same walker.","summary":"In the Linux arm64 KVM hypervisor, the per-CPU hyp stack pages were not removed from the host stage-2 mapping during ownership transfer, because the fix walked only the linear-map alias and missed the private VA range. The sources do not state what an attacker gains from this beyond the mapping inconsistency.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["arm64","infrastructure","kvm","linux-kernel","self-hosted"],"not_affected_if":["no-kvm","x86-host"],"how_to_check":"- unknown","fix":"- Update the Linux kernel to a release that includes the upstream commit titled 'KVM: arm64: Transfer the hyp stack pages out of the host stage-2' (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":"2026-10-25T05:27:09+00:00","updated_at":"2026-10-25T05:27:09+00:00","category":"infrastructure","confidence":0.35,"triage":{"at":"2026-10-25T05:27:09Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a release that includes the upstream commit titled 'KVM: arm64: Transfer the hyp stack pages out of the host stage-2' (version unknown from the sources)","reach":"local","title":"Linux kernel KVM arm64: hypervisor stack pages left mapped to host","impact":"medium","summary":"In the Linux arm64 KVM hypervisor, the per-CPU hyp stack pages were not removed from the host stage-2 mapping during ownership transfer, because the fix walked only the linear-map alias and missed the private VA range. The sources do not state what an attacker gains from this beyond the mapping inconsistency.","category":"infrastructure","nicknames":[],"who_cares":["linux-kernel","arm64","kvm","self-hosted"],"confidence":0.35,"needs_auth":"unknown","worst_case":"unknown; host stage-2 mapping of hyp stack pages","analyst_note":"Check the NVD entry and the upstream kernel commit for the affected version range and the exact security impact.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-kvm","x86-host"],"who_is_affected":"Systems running Linux on arm64 hosts that use KVM to run virtual machines are the ones where this code path runs. Systems without KVM on arm64, and x86 hosts, are not affected by this code. The sources do not say which kernel versions are vulnerable.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000602,"input_tokens":3345,"output_tokens":535,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2':47B,105C '-2026':13A,16A '-98466':14A,17A 'alia':61B,115C 'arm64':4A,18B,30B,94C 'attack':75B 'beyond':79B 'cpu':36B,124C 'cve':12A,15A 'fix':54B,106C 'follow':88C 'gain':76B 'guard':135C 'host':11A,26B,45B,103C,107C 'hyp':37B,97C,125C 'hypervisor':5A,32B 'inconsist':82B 'infrastructur':19B 'kernel':2A,23B,86C 'kvm':3A,20B,31B,93C 'left':8A 'linear':59B,113C 'linear-map':58B,112C 'linux':1A,22B,29B,85C 'linux-kernel':21B 'map':9A,48B,60B,81B,114C,127C 'memblock':118C 'miss':63B 'none':138C 'ownership':50B,108C 'page':7A,39B,99C,136C 'per':35B,123C 'per-cpu':34B,122C 'privat':65B,130C 'rang':67B,132C,144C 'region':119C 'remov':42B 'resolv':92C 'self':25B 'self-host':24B 'sourc':69B 'stack':6A,38B,98C,126C,141C 'stage':46B,104C 'state':72B 'transfer':51B,95C 'va':66B,131C,143C 'vulner':89C 'walk':55B,109C,139C 'walker':148C","nicknames":[],"mitigations":[],"who_affected":"Systems running Linux on arm64 hosts that use KVM to run virtual machines are the ones where this code path runs. Systems without KVM on arm64, and x86 hosts, are not affected by this code. The sources do not say which kernel versions are vulnerable.","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-2026-98466","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98466","severity":null,"published_at":"2026-10-18T16:16:57+00:00","modified_at":"2026-10-19T10:18:56+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"}