{"api_version":"1","generated_at":"2026-10-27T03:18:28+00:00","cve":"CVE-2026-98466","urls":{"html":"https://cve.report/CVE-2026-98466","api":"https://cve.report/api/cve/CVE-2026-98466.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98466","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98466"},"summary":{"title":"KVM: arm64: Transfer the hyp stack pages out of the host stage-2","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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-18 16:16:57","updated_at":"2026-10-24 14:16:43"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.2","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","data":{"baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/e5dd2a91a7ae3a276e6d79806127e923936e241b","name":"https://git.kernel.org/stable/c/e5dd2a91a7ae3a276e6d79806127e923936e241b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/22df195bff84300a3f04813d6148765c77ac565a","name":"https://git.kernel.org/stable/c/22df195bff84300a3f04813d6148765c77ac565a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3a8c562892b96f35bba1e00d5e455a15963bbb92","name":"https://git.kernel.org/stable/c/3a8c562892b96f35bba1e00d5e455a15963bbb92","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98466","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98466","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a919b17ef012ca0572bae759c27e5ea02bfb47f e5dd2a91a7ae3a276e6d79806127e923936e241b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a919b17ef012ca0572bae759c27e5ea02bfb47f 22df195bff84300a3f04813d6148765c77ac565a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1a919b17ef012ca0572bae759c27e5ea02bfb47f 3a8c562892b96f35bba1e00d5e455a15963bbb92 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.19","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.55 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.9 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["arch/arm64/kvm/hyp/nvhe/setup.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"e5dd2a91a7ae3a276e6d79806127e923936e241b","status":"affected","version":"1a919b17ef012ca0572bae759c27e5ea02bfb47f","versionType":"git"},{"lessThan":"22df195bff84300a3f04813d6148765c77ac565a","status":"affected","version":"1a919b17ef012ca0572bae759c27e5ea02bfb47f","versionType":"git"},{"lessThan":"3a8c562892b96f35bba1e00d5e455a15963bbb92","status":"affected","version":"1a919b17ef012ca0572bae759c27e5ea02bfb47f","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["arch/arm64/kvm/hyp/nvhe/setup.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.19"},{"lessThan":"5.19","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.55","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.55","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.9","versionStartIncluding":"5.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"5.19","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The local `module_init(kvm_arm_init)` path reaches `init_hyp_mode()` → `kvm_hyp_init_protection()` → `do_pkvm_init()` → `handle___pkvm_init()` → `__pkvm_init()` → `__pkvm_init_finalise()` → patched `fix_host_ownership()`. Exploitation accesses the omitted stack pages through host direct-map aliases; no wire or guest message supplies causal data.\nAC:L - With `kvm-arm.mode=protected`, the omitted pages retain host-owned state, so `handle_host_mem_abort()` → `host_stage2_idmap()` deterministically installs `PKVM_HOST_MEM_PROT` RWX mappings. The attacker controls the stack access and a following HVC; no race or external condition is required.\nPR:H - `/dev/kvm` ioctls only cause EL2 to use the stack; they do not expose `kvm_arm_hyp_stack_base` or its PFN. Writing the kernel direct-map alias requires control of host EL1 through real host-administrative privilege, unavailable through user namespaces.\nUI:N - After pKVM initialization, the host attacker can access the retained direct-map alias and invoke an HVC or `KVM_RUN` to make EL2 use the corrupted stack. No action by another user is required.\nS:C - The missing `host_stage2_set_owner_locked(..., PKVM_ID_HYP)` operation lets the host EL1 authority access the protected EL2 stack, crossing the stage-2 boundary that isolates the hypervisor and protected VMs.\nC:H - The host can read live EL2 stack contents, including saved registers and pointers. Its simultaneous write access to stack control data can hijack EL2 execution and expose hypervisor or protected-VM memory.\nI:H - The host can overwrite the active stack used by `__host_exit()` and `handle_trap()`, including saved frame and return state. Control-flow corruption at EL2 can modify hypervisor ownership metadata and protected-VM memory.\nA:H - Corrupting the per-CPU stack consumed on every host-to-EL2 trap can produce invalid returns or hypervisor faults, crashing the hypervisor and consequently the host or its protected VMs."}]}],"providerMetadata":{"dateUpdated":"2026-10-24T14:08:58.562Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e5dd2a91a7ae3a276e6d79806127e923936e241b"},{"url":"https://git.kernel.org/stable/c/22df195bff84300a3f04813d6148765c77ac565a"},{"url":"https://git.kernel.org/stable/c/3a8c562892b96f35bba1e00d5e455a15963bbb92"}],"title":"KVM: arm64: Transfer the hyp stack pages out of the host stage-2","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98466","datePublished":"2026-10-18T15:15:18.414Z","dateReserved":"2026-09-25T10:25:14.351Z","dateUpdated":"2026-10-24T14:08:58.562Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-18 16:16:57","lastModifiedDate":"2026-10-24 14:16:43","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.5,"impactScore":6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98466","Ordinal":"1","Title":"KVM: arm64: Transfer the hyp stack pages out of the host stage-2","CVE":"CVE-2026-98466","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98466","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"KVM: arm64: Transfer the hyp stack pages out of the host stage-2"}]}}}