Live › vulnerability › CVE-2026-98713
Go to dashboardThe Linux kernel's arm64 KVM hypervisor now injects fine-grained UNDEF traps even on hardware without FEAT_FGT, fixing a spurious kernel WARN when a guest runs a TLBI OS operation. The sources describe a correctness fix and do not state an attacker-controlled impact.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Hosts running the Linux kernel with KVM on arm64 hardware that hosts guests at vEL1 without FEAT_FGT, where a guest may issue TLBI OS operations. Systems on x86 or without KVM virtualization are not affected by this change. The sources do not say whether any exploitable condition exists beyond the spurious WARN.
No product ranges from the sources yet.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT
FGUs don't actually require hardware support, so don't gate fgt trap config insertion on FGT. This is the only action required to allow FGUs always, as kvm_calculate_traps() already computes the FGU bits with or without FEAT_FGT.
This also fixes a spurious WARN when a TLBI OS is run on a guest in vEL1 without FEAT_TLBIOS on non FEAT_FGT hardware. In this configuration the course-grained HCR_EL2.TTLBOS trap reaches the handler handle_tlbi_el1(), which expects an EL1 TLBI only from vEL2. With FGUs enabled the UNDEF will be injected without needing the specific handler.
[oliver: Take Wei-Lin's suggested changelog]
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