CVE-2026-72280

Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source

AV:LAttack vector, local

The flaw is reached when guest code in a nested KVM context executes an MSR/MRS to ZCR_EL2 that traps to EL2, traversing KVM_RUN → hyp fast-path kvm_hyp_handle_zcr_el2() → kvm_hyp_handle_fpsimd(); this requires local guest execution on an arm64 VHE KVM host, not remote network input.

AC:LAttack complexity, low

On arm64 VHE hosts with nested virtualization (FEAT_NV2) and SVE enabled, a tenant guest in nested context (L1 non-hyp or L2) can deterministically issue the ZCR_EL2 access that hits the bogus WARN; the attacker controls the trap timing and FP/SVE lazy-switch preconditions without uncontrollable host races.

PR:NPrivileges required, none

No host root or init-namespace capabilities are required—exploitation needs only code execution inside an assigned KVM guest with nested virtualization and SVE enabled (typical nested-virt ARM cloud tenant), not privileged access on the physical host itself.

UI:NUser interaction, none

No victim user or administrator action is required beyond the attacker operating their own nested/SVE-enabled guest workload; triggering is fully automated via a single guest MSR to ZCR_EL2 that traps into the hypervisor fast path.

S:CScope, changed

A guest-triggered WARN in EL2 hypervisor code escalates to hyp_panic(), crashing the host kernel and denying all co-resident VMs—crossing the guest-to-host KVM virtualization security boundary even though exploitation is denial-of-service rather than memory corruption.

C:NConfidentiality impact, none

The failure mode is WARN_ON_ONCE → hyp_panic with no out-of-bounds access, use-after-free, or memory corruption; it is a deterministic hypervisor assertion panic without an information disclosure or memory-read primitive.

I:NIntegrity impact, none

No guest-controlled kernel memory write or control-flow hijack occurs; the bogus WARN aborts via hyp_panic before any exploitable state mutation beyond crashing the host, and the removed check was incorrectly rejecting a legitimate nested ZCR_EL2 write path.

A:HAvailability impact, high

WARN_ON_ONCE in EL2 with hyp vectors installed invokes hyp_panic() and host panic(), immediately denying availability of the hypervisor and every VM on the affected arm64 KVM host; the attack is repeatable on each ZCR_EL2 trap while nested virt and SVE remain enabled.