Answer in brief
CVE-2026-74516 records a Unknown severity vulnerability in KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=091abbf578f926e763adc0f577baeb7f405b4bdc <6664a5aea45318f4ec156a729949b474dd6e3159 || >=091abbf578f926e763adc0f577baeb7f405b4bdc <f12373625b4dc9bcc89c41872648878c73bb9272 || >=091abbf578f926e763adc0f577baeb7f405b4bdc <7668c58dcf465559dc7a0d2e95e9cb79cf47454b || >=091abbf578f926e763adc0f577baeb7f405b4bdc <89f9e8398e79c49886766fc24a84c37726231104 || >=091abbf578f926e763adc0f577baeb7f405b4bdc <7d3aae206663c4e006b25a1c7a20a4029e67da76 | 6664a5aea45318f4ec156a729949b474dd6e3159, f12373625b4dc9bcc89c41872648878c73bb9272, 7668c58dcf465559dc7a0d2e95e9cb79cf47454b, 89f9e8398e79c49886766fc24a84c37726231104, 7d3aae206663c4e006b25a1c7a20a4029e67da76 |
| Linux/Linuxgeneric | 6.0 | Not reported |
Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 15, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active Always update x2APIC MSR intercepts for L1 when AVIC is deactivated, even if L2 is active and KVM is using a separate MSR bitmap to run L2. If AVIC is fully enabled prior to running L2, and is then inhibited while L2 is active (for a VM-scoped inhibit), then KVM will run L1 with AVIC disabled, but with x2APIC MSR intercepts disabled, i.e. will allow L1 to read most of the host's APIC state, send arbitrary interrupts, change task priority, and ultimately trivially DoS the host. E.g. sending a self-IPI in L1 on HYPERV_REENLIGHTENMENT_VECTOR, 0xee, with CONFIG_HYPERV=n in the host kernel as a "safe" PoC, yields: Spurious interrupt (vector 0xee) on CPU#425. Acked And hacking KVM to abuse kvm_set_posted_intr_wakeup_handler() to register a handler and WARN on POSTED_INTR_WAKEUP_VECTOR yields: ------------[ cut here ]------------ WARNING: arch/x86/kvm/svm/svm.c:5594 at pi_wakeup_handler+0x9/0x10 [kvm_amd], CPU#156: nested_x2apic_t/316940 CPU: 156 UID: 0 PID: 316940 Comm: nested_x2apic_t Tainted: G S U Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER Hardware name: Google Astoria-Turin/astoria, BIOS 0.20260209.0-0 02/09/2026 RIP: 0010:pi_wakeup_handler+0x9/0x10 [kvm_amd] Call Trace: <IRQ> sysvec_kvm_posted_intr_wakeup_ipi+0x64/0x80 </IRQ> <TASK> asm_sysvec_kvm_posted_intr_wakeup_ipi+0x1a/0x20 RIP: 0010:vcpu_run+0x1430/0x1e40 [kvm] kvm_arch_vcpu_ioctl_run+0x2c1/0x600 [kvm] kvm_vcpu_ioctl+0x580/0x6b0 [kvm] __se_sys_ioctl+0x6d/0xb0 do_syscall_64+0x10a/0x480 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x46ff4b </TASK> ---[ end trace 0000000000000000 ]---
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-74516 records a Unknown severity vulnerability in KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=091abbf578f926e763adc0f577baeb7f405b4bdc <6664a5aea45318f4ec156a729949b474dd6e3159 || >=091abbf578f926e763adc0f577baeb7f405b4bdc <f12373625b4dc9bcc89c41872648878c73bb9272 || >=091abbf578f926e763adc0f577baeb7f405b4bdc <7668c58dcf465559dc7a0d2e95e9cb79cf47454b || >=091abbf578f926e763adc0f577baeb7f405b4bdc <89f9e8398e79c49886766fc24a84c37726231104 || >=091abbf578f926e763adc0f577baeb7f405b4bdc <7d3aae206663c4e006b25a1c7a20a4029e67da76 | 6664a5aea45318f4ec156a729949b474dd6e3159, f12373625b4dc9bcc89c41872648878c73bb9272, 7668c58dcf465559dc7a0d2e95e9cb79cf47454b, 89f9e8398e79c49886766fc24a84c37726231104, 7d3aae206663c4e006b25a1c7a20a4029e67da76 |
| Linux/Linuxgeneric | 6.0 | Not reported |
Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 15, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active Always update x2APIC MSR intercepts for L1 when AVIC is deactivated, even if L2 is active and KVM is using a separate MSR bitmap to run L2. If AVIC is fully enabled prior to running L2, and is then inhibited while L2 is active (for a VM-scoped inhibit), then KVM will run L1 with AVIC disabled, but with x2APIC MSR intercepts disabled, i.e. will allow L1 to read most of the host's APIC state, send arbitrary interrupts, change task priority, and ultimately trivially DoS the host. E.g. sending a self-IPI in L1 on HYPERV_REENLIGHTENMENT_VECTOR, 0xee, with CONFIG_HYPERV=n in the host kernel as a "safe" PoC, yields: Spurious interrupt (vector 0xee) on CPU#425. Acked And hacking KVM to abuse kvm_set_posted_intr_wakeup_handler() to register a handler and WARN on POSTED_INTR_WAKEUP_VECTOR yields: ------------[ cut here ]------------ WARNING: arch/x86/kvm/svm/svm.c:5594 at pi_wakeup_handler+0x9/0x10 [kvm_amd], CPU#156: nested_x2apic_t/316940 CPU: 156 UID: 0 PID: 316940 Comm: nested_x2apic_t Tainted: G S U Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER Hardware name: Google Astoria-Turin/astoria, BIOS 0.20260209.0-0 02/09/2026 RIP: 0010:pi_wakeup_handler+0x9/0x10 [kvm_amd] Call Trace: <IRQ> sysvec_kvm_posted_intr_wakeup_ipi+0x64/0x80 </IRQ> <TASK> asm_sysvec_kvm_posted_intr_wakeup_ipi+0x1a/0x20 RIP: 0010:vcpu_run+0x1430/0x1e40 [kvm] kvm_arch_vcpu_ioctl_run+0x2c1/0x600 [kvm] kvm_vcpu_ioctl+0x580/0x6b0 [kvm] __se_sys_ioctl+0x6d/0xb0 do_syscall_64+0x10a/0x480 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x46ff4b </TASK> ---[ end trace 0000000000000000 ]---
Quoted source text, attributed separately from HOL analysis.