Bug 2467018 (CVE-2026-43096)

Summary: CVE-2026-43096 kernel: mshv: Fix infinite fault loop on permission-denied GPA intercepts
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's mshv component. A malicious guest operating system could exploit this by attempting to write to read-only memory regions or execute code in non-executable regions. This can lead to an infinite fault loop, causing the virtual CPU (vCPU) to spin indefinitely and consume host resources, resulting in a Denial of Service (DoS) for the host system.
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Description OSIDB Bzimport 2026-05-06 10:03:24 UTC
In the Linux kernel, the following vulnerability has been resolved:

mshv: Fix infinite fault loop on permission-denied GPA intercepts

Prevent infinite fault loops when guests access memory regions without
proper permissions. Currently, mshv_handle_gpa_intercept() attempts to
remap pages for all faults on movable memory regions, regardless of
whether the access type is permitted. When a guest writes to a read-only
region, the remap succeeds but the region remains read-only, causing
immediate re-fault and spinning the vCPU indefinitely.

Validate intercept access type against region permissions before
attempting remaps. Reject writes to non-writable regions and executes to
non-executable regions early, returning false to let the VMM handle the
intercept appropriately.

This also closes a potential DoS vector where malicious guests could
intentionally trigger these fault loops to consume host resources.