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CVE-2026-63806 is a denial-of-service vulnerability in the Linux kernel's KVM subsystem on x86 in ioeventfd datamatch handling. The flaw arises when KVM emulates a guest store whose destination spans a page boundary and the second page is handled as emulated MMIO with a datamatch-enabled ioeventfd at offset 0. In this path, KVM uses the emulation context's destination buffer as the source for the fragmented write and may pass a pointer into that buffer at an offset that is not naturally aligned for the compared length. The ioeventfd datamatch code contained a reachable BUG_ON() that assumed alignment of the value pointer; a crafted guest store can violate that assumption and trigger the BUG. The upstream fix replaces the alignment-sensitive access with get_unaligned(), eliminating the guest-reachable kernel assertion while preserving functionality.
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No public exploit code observed for this vulnerability.
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
1 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
No news coverage yet. Advisories and community discussion only.
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Every observed campaign linking this CVE to a named adversary.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.