{"id":"CVE-2026-98467","revision":"395a37a83e7146b0a8b381385d569bec","records":[{"revision":"395a37a83e7146b0a8b381385d569bec","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98467","aliases":[],"title":"KVM: arm64: nv: Fix null ptr deref on nested wp/unmap, teardown race","description":"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.","state":0,"publishedAt":"2026-10-18T15:15:19.294+00:00","modifiedAt":"2026-10-19T09:20:05.363+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/arm64/kvm/nested.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7270cc9157f474dfc46750a34c9d7defc686b2eb\",\n                            \"lessThan\": \"970de111c087488e53cadf5480b94e0f695db985\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7270cc9157f474dfc46750a34c9d7defc686b2eb\",\n                            \"lessThan\": \"3cefc1ab511fad6a0f708e7a4aee9f91346e9457\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"7270cc9157f474dfc46750a34c9d7defc686b2eb\",\n                            \"lessThan\": \"4c74e233cdedd11592775fae2a6243e67ca3f891\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"arch/arm64/kvm/nested.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.16\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.16\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.55\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.9\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/970de111c087488e53cadf5480b94e0f695db985","https://git.kernel.org/stable/c/3cefc1ab511fad6a0f708e7a4aee9f91346e9457","https://git.kernel.org/stable/c/4c74e233cdedd11592775fae2a6243e67ca3f891"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98467","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98467","identifiers":["CVE-2026-98467"]},"retained":false,"historicalAffected":[]}],"coverage":[]}