Acknowledged
Created: Feb 27, 2025
Updated: Jun 17, 2025
Found In Version: 10.21.20.1
Severity: Standard
Applicable for: Wind River Linux LTS 21
Component/s: Kernel
In the Linux kernel, the following vulnerability has been resolved:KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernelAdvertise support for Hyper-V's SEND_IPI and SEND_IPI_EX hypercalls if andonly if the local API is emulated/virtualized by KVM, and explicitly rejectsaid hypercalls if the local APIC is emulated in userspace, i.e. don't relyon userspace to opt-in to KVM_CAP_HYPERV_ENFORCE_CPUID.Rejecting SEND_IPI and SEND_IPI_EX fixes a NULL-pointer dereference ifHyper-V enlightenments are exposed to the guest without an in-kernel localAPIC: dump_stack+0xbe/0xfd __kasan_report.cold+0x34/0x84 kasan_report+0x3a/0x50 __apic_accept_irq+0x3a/0x5c0 kvm_hv_send_ipi.isra.0+0x34e/0x820 kvm_hv_hypercall+0x8d9/0x9d0 kvm_emulate_hypercall+0x506/0x7e0 __vmx_handle_exit+0x283/0xb60 vmx_handle_exit+0x1d/0xd0 vcpu_enter_guest+0x16b0/0x24c0 vcpu_run+0xc0/0x550 kvm_arch_vcpu_ioctl_run+0x170/0x6d0 kvm_vcpu_ioctl+0x413/0xb20 __se_sys_ioctl+0x111/0x160 do_syscal1_64+0x30/0x40 entry_SYSCALL_64_after_hwframe+0x67/0xd1Note, checking the sending vCPU is sufficient, as the per-VM irqchip_modecan't be modified after vCPUs are created, i.e. if one vCPU has anin-kernel local APIC, then all vCPUs have an in-kernel local APIC.
CREATE(Triage):(User=admin) CVE-2025-21779 (https://nvd.nist.gov/vuln/detail/CVE-2025-21779)
