Answer in brief
CVE-2026-99082 records a High severity (CVSS 8.8) vulnerability in KVM: x86: Use active memslots for the per-vCPU MMIO cache. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=699023e239658e62da6f42f47d31b54788521ec1 <a63f79d9da9468952396af73e1e53330845cf876 || >=699023e239658e62da6f42f47d31b54788521ec1 <7fd4e64f4bbc8c35ae8f0d2a1fb5b77a76d5b4fd || >=699023e239658e62da6f42f47d31b54788521ec1 <2566780c684c9c21241d409d790087c73070f312 || >=699023e239658e62da6f42f47d31b54788521ec1 <e792a9ace39d2812a5b342a1987186c7bc653204 || >=699023e239658e62da6f42f47d31b54788521ec1 <b3e6212dea2e4328a841ceb37f377583176dc735 | a63f79d9da9468952396af73e1e53330845cf876, 7fd4e64f4bbc8c35ae8f0d2a1fb5b77a76d5b4fd, 2566780c684c9c21241d409d790087c73070f312, e792a9ace39d2812a5b342a1987186c7bc653204, b3e6212dea2e4328a841ceb37f377583176dc735 |
| Linux/Linuxgeneric | 4.2 | Not reported |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Use active memslots for the per-vCPU MMIO cache KVM tags the per-vCPU MMIO cache with a memslot generation so that a memslot update invalidates cached MMIO information. Both the fill and validation paths use kvm_memslots(), which unconditionally selects address space 0, even when the vCPU is running in SMM and using address space 1. Commit 56f17dd3fbc4 ("kvm: x86: fix stale mmio cache bug") added the memslot generation to the cache key so that a memslot update could not leave a stale entry valid. When commit 699023e23965 ("KVM: x86: add SMM to the MMU role, support SMRAM address space") added the SMM address space, these helpers were not converted to use the active memslots. Consequently, an update to the SMM memslots can leave an entry from the old SMM address space apparently valid after the vCPU returns to the normal address space. A guest can then cause an access to valid RAM at the same GFN to be returned to userspace as KVM_EXIT_MMIO. Completing that exit through the VMM's RAM address space writes the backing page without going through KVM's write-tracking path. If the page backs a nested EPT table, KVM can continue using shadow translations derived from the old contents. The WARN_ON_ONCE() in kvm_mmu_write_protect_fault() catches this invalid cache and memslot combination. Use the vCPU's active memslots when caching and validating the entry. Memslot generations are unique across address spaces, so the generation also distinguishes the normal and SMM views. This matches the MMIO SPTE cache, which already uses kvm_vcpu_memslots(). On an unpatched current-mainline kernel, a regression test that fills the cache in SMM and updates only the SMM memslots fails the intended RAM write and triggers the kvm_mmu_write_protect_fault() warning. With this change, the same test completes the RAM write without a warning. The x86/smm_test, set_memory_region_test, and memslot_modification_stress_test selftests also pass.
Quoted source text, attributed separately from HOL analysis.