{"schema":"threatline.record/2","record":{"id":"CVE-2026-98467","aliases":[],"summary":"KVM: arm64: nv: Fix null ptr deref on nested wp/unmap, teardown race","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: nv: Fix null ptr deref on nested wp/unmap, teardown race\n\nCommit 7270cc9157f4 (\"KVM: arm64: nv: Handle VNCR_EL2 invalidation from MMU\nnotifiers\") introduced VNCR_EL2 invalidation in both kvm_nested_s2_unmap()\nand kvm_nested_s2_wp().\n\nHowever at the point of this being performed concurrent stage 2 teardown of\na nested guest can cause kvm->arch.mmu.pgt to be set to NULL.\n\nThis happens in kvm_flush_shadow_all() -> kvm_arch_flush_shadow_all() ->\nkvm_free_stage2_pgd() and is performed under the kvm->mmu_lock.\n\nCommit ec14c272408a (\"KVM: arm64: nv: Unmap/flush shadow stage 2 page\ntables\") introduced the teardown of the entire nested MMU range, which then\ninvokes stage2_apply_range() with resched=true:\n\nmmu_notifier_invalidate_range_start()\n  -> ... -> kvm_mmu_notifier_invalidate_range_start()\n    -> kvm_mmu_unmap_gfn_range()\n      -> kvm_unmap_gfn_range()\n        -> kvm_nested_s2_unmap()\n          -> kvm_stage2_unmap_range()\n            -> __unmap_stage2_range()\n                -> stage2_apply_range()\n\nThis means that stage2_apply_range() can drop the kvm->mmu_lock and thus\nconcurrent progress can be made in lockstep with\nkvm_arch_flush_shadow_all().\n\nIf kvm_arch_flush_shadow_all() advances ahead of stage2_apply_range() and\ncompletes its operation it guarantees a NULL pointer deref.\n\nSince kvm_free_stage2_pgd() is performed under the kvm->mmu_lock this will\neither be observed NULL or not and serialised against\nkvm_free_stage2_pgd().\n\nResolve the issue by abstracting the invalidation to a new function,\nkvm_invalidate_vncr_ipa_all(), and check that the pgt is non-NULL before\ndereferencing it.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98467","source_modified_at":"2026-10-19T09:20:05.363Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"7270cc9157f474dfc46750a34c9d7defc686b2eb","lessThan":"970de111c087488e53cadf5480b94e0f695db985","status":"affected","versionType":"git"},{"version":"7270cc9157f474dfc46750a34c9d7defc686b2eb","lessThan":"3cefc1ab511fad6a0f708e7a4aee9f91346e9457","status":"affected","versionType":"git"},{"version":"7270cc9157f474dfc46750a34c9d7defc686b2eb","lessThan":"4c74e233cdedd11592775fae2a6243e67ca3f891","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98467","source_modified_at":"2026-10-19T09:20:05.363Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"6.16","status":"affected"},{"version":"0","lessThan":"6.16","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98467","source_modified_at":"2026-10-19T09:20:05.363Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"970de111c087488e53cadf5480b94e0f695db985","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98467","source_modified_at":"2026-10-19T09:20:05.363Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"3cefc1ab511fad6a0f708e7a4aee9f91346e9457","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98467","source_modified_at":"2026-10-19T09:20:05.363Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"4c74e233cdedd11592775fae2a6243e67ca3f891","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00166,"percentile":0.05521,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:15:19.294Z","modified_at":"2026-10-19T09:20:05.363Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98467","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:20:05.363Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98467","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/970de111c087488e53cadf5480b94e0f695db985"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/3cefc1ab511fad6a0f708e7a4aee9f91346e9457"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/4c74e233cdedd11592775fae2a6243e67ca3f891"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:20:05.363Z","content_hash":"e5fa8e876ee4372d6b1bc77ac17501f72593725d5ef4193d0f92695b6d737345"}}