In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: WARN and clear role.invalid when creating a child shadow page Explicitly clear role.invalid when deriving a child shadow page's role from its parent to harden against bugs elsewhere in KVM, as violating KVM's invariant that invalid pages are NOT on the list of active MMU pages leads to use-after-free due to __kvm_mmu_prepare_zap_page() using list_add() instead of list_move() when processing an invalid shadow page, i.e. makes a bad situation far worse. Yell loudly if the parent is invalid, as it means KVM has missed a validity check, i.e. KVM is attempting to map memory using an invalid/obsolete root, but continue on as the child is otherwise still a valid shadow page. ================================================================== BUG: KASAN: slab-use-after-free in __kvm_mmu_get_shadow_page+0x1817/0x1860 [kvm] Write of size 8 at addr ff11000153dd1368 by task repro/853 CPU: 1 UID: 1000 PID:
Casky was already ahead
This CVE exploits attack patterns that Casky's 0matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.
CVE-2026-80726 is a critical memory safety vulnerability in the Linux kernel's KVM (Kernel-based Virtual Machine) hypervisor affecting the x86 MMU (Memory Management Unit) shadow paging mechanism. The flaw occurs when a child shadow page's role is derived from its parent without properly clearing the invalid flag, violating KVM's core invariant that invalid pages must not exist on the active MMU pages list. This invariant violation leads to use-after-free conditions when __kvm_mmu_prepare_zap_page() incorrectly processes invalid shadow pages using list_add() instead of list_move(), allowing memory corruption within the hypervisor. Any organization running KVM-based virtualization on affected Linux kernels—including cloud providers, enterprise hypervisors, and containerized environments—face potential VM escape scenarios and privilege escalation risks, making this a critical threat to multi-tenant infrastructure and host system integrity.
While this CVE lacks direct MITRE ATT&CK technique mappings, Casky.ai's Claude-powered analysis engine would detect attack patterns associated with T1055 (Process Injection) and T1548 (Abuse Elevation Control Mechanism) by recognizing the use-after-free exploitation pathway and memory corruption signatures within hypervisor logs and kernel memory dumps. Practitioners using Casky would observe findings highlighting: (1) suspicious shadow page allocation patterns deviating from expected MMU state transitions, (2) invalid page list corruption indicators in memory forensics, and (3) anomalous zap_page() call sequences that violate expected MMU page lifecycle consistency. The platform's extended reasoning would correlate these signals across the 754 security skills to identify this as a memory safety defect enabling privileged code execution within the hypervisor—categorizing it as infrastructure-layer compromise requiring immediate kernel patching and guest VM isolation.
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