{"id":"CVE-2026-89908","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: KVM: Preserve memslot arch flags on KVM_MR_FLAGS_ONLY\n\nkvm_arch_prepare_memory_region() computes new->arch.flags, i.e","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: KVM: Preserve memslot arch flags on KVM_MR_FLAGS_ONLY\n\nkvm_arch_prepare_memory_region() computes new->arch.flags, i.e. whether\na memslot is KVM_MEM_HUGEPAGE_…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c < 7c6df65b53846cd7a9a1c81c6ddb42fdc08603e8","Linux >= 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c < 4e4dbc341b1581dc512b85d98b768373b0398366","Linux >= 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c < bc7a6849b4395f45a602db91b0fb2fb2e9ed4bba","Linux >= 7ab6fb505b2a7447c4a7237a12c59e3ad0c7298c < 27a9bfee3bbcb3cabb77797354f07e0e44e49831","Linux 6.8"],"published":"2026-09-16","updated":"2026-09-16","sourceUpdated":"2026-09-16T15:18:17.050","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89908","references":[{"url":"https://git.kernel.org/stable/c/27a9bfee3bbcb3cabb77797354f07e0e44e49831","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4e4dbc341b1581dc512b85d98b768373b0398366","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7c6df65b53846cd7a9a1c81c6ddb42fdc08603e8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bc7a6849b4395f45a602db91b0fb2fb2e9ed4bba","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-16T10:53:53.976Z","epss":0.00163,"epssPercentile":0.05961,"slug":"CVE-2026-89908","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: KVM: Preserve memslot arch flags on KVM_MR_FLAGS_ONLY\n\nkvm_arch_prepare_memory_region() computes new->arch.flags, i.e. whether\na memslot is KVM_MEM_HUGEPAGE_CAPABLE or KVM_MEM_HUGEPAGE_INCAPABLE,\nonly for KVM_MR_CREATE and KVM_MR_MOVE, and returns early for every\nother change. But the generic code allocates a zeroed memslot for every\nchange and never copies old->arch, so after a KVM_MR_FLAGS_ONLY update,\ne.g. toggling KVM_MEM_LOG_DIRTY_PAGES for live migration, the active\nmemslot has arch.flags == 0.\n\nWith both flags clear, fault_supports_huge_mapping() falls through to\nthe alignment check on the HVA range alone, which no longer verifies\nthat the GPA and HVA have the same offset within a PMD. A memslot that\nwas marked KVM_MEM_HUGEPAGE_INCAPABLE because of a GPA/HVA offset\nmismatch can then be mapped with PMD entries on read faults, and since\nkvm_map_page() aligns the gfn and the pfn independently, the guest ends\nup accessing the wrong host pages, exactly the \"d -> f, e -> g\" case\ndescribed in the comment above the check.\n\nCarry the arch flags over from the old memslot for KVM_MR_FLAGS_ONLY,\nas the GPA, HVA and size are guaranteed to be unchanged for that case.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":205138,"id":"CVE-2026-89908","ts":1789570705423,"field":"cvss","old":null,"new":"8.8"},{"seq":205137,"id":"CVE-2026-89908","ts":1789570705423,"field":"severity","old":"none","new":"high"}]}