CVE-2026-74517

CRITICALCVSS 9.3/10EPSS 0.13%

Last modified

CVE-2026-74517 is a critical-severity vulnerability rated 9.3/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Cancel delayed I/O APIC EOI handling before destroying vCPUs Cancel (and flush) the I/O APIC's delayed EOI handling work during the "pre VM destroy" phase, before vCPUs are destroyed, as processing the EOI broadcast will inject another IRQ if the line is asserted, i.e. will try to deliver an IRQ to the target vCPU(s). EPSS estimates a 0.13% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Cancel delayed I/O APIC EOI handling before destroying vCPUs Cancel (and flush) the I/O APIC's delayed EOI handling work during the "pre VM destroy" phase, before vCPUs are destroyed, as processing the EOI broadcast will inject another IRQ if the line is asserted, i.e. will try to deliver an IRQ to the target vCPU(s). Canceling the work after vCPUs are destroyed leads to UAF if the delayed work is processed after vCPUs are destroyed. BUG: KASAN: slab-use-after-free in __kvm_irq_delivery_to_apic_fast+0x9bf/0xa20 arch/x86/kvm/lapic.c:1250 Read of size 8 at addr ffff8880499abea0 by task kworker/1:2/1218 CPU: 1 UID: 0 PID: 1218 Comm: kworker/1:2 Not tainted 7.1.0-rc7 #5 PREEMPT(lazy) Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: events kvm_ioapic_eoi_inject_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 print_report+0x139/0x4ad mm/kasan/report.c:482 kasan_report+0xe4/0x1d0 mm/kasan/report.c:595 __kvm_irq_delivery_to_apic_fast+0x9bf/0xa20 arch/x86/kvm/lapic.c:1250 __kvm_irq_delivery_to_apic+0xd8/0xbf0 arch/x86/kvm/lapic.c:1345 kvm_irq_delivery_to_apic arch/x86/kvm/lapic.h:129 ioapic_service+0x308/0x590 arch/x86/kvm/ioapic.c:492 kvm_ioapic_eoi_inject_work+0x13c/0x190 arch/x86/kvm/ioapic.c:532 process_one_work+0xa59/0x19a0 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 worker_thread+0x5eb/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> Note, the VM is unreachable once kvm_destroy_vm() starts, and scheduling new work via kvm_ioapic_send_eoi() can only be done via KVM_RUN, i.e. requires a live vCPU. Alternatively, KVM could simply destroy the I/O APIC during the "pre" phase of VM destruction, but that gets more than a bit sketchy as KVM expects the I/O APIC to exist if ioapic_in_kernel() is true, and nested virtualization in particular has a bad habit of touching VM-scope state during vCPU destruction. E.g. attempting to free the PIC during the pre phase would lead to a NULL pointer dereference in kvm_cpu_has_extint(), and it's not hard to imagine the I/O APIC having a similar flaw.

Metrics

CVSS 3.1
9.3/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS Probability
0.13%

3.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= c60f5156e62d0be6c53373b623f16a9e37e2208e, < 69d040448067cebdd5598684db36ce7d8fb2f43e; >= 17bcd714426386fda741a4bccd96a2870179344b, < 5f0a99ea721203a4063618aafcca32abf573cb96; >= 17bcd714426386fda741a4bccd96a2870179344b, < ed56a6b58222f9c1f4115a0bd2788dd6ed6022e2; >= 17bcd714426386fda741a4bccd96a2870179344b, < 9910e835580fef3bef53b70241dd00c4bffad693; >= 6.12.41, < 6.12.105
LinuxLinux6.14

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74517?
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Cancel delayed I/O APIC EOI handling before destroying vCPUs Cancel (and flush) the I/O APIC's delayed EOI handling work during the "pre VM destroy" phase, before vCPUs are destroyed, as processing the EOI broadcast will inject another IRQ if the line is asserted, i.e. will try to deliver an IRQ to the target vCPU(s). Canceling the work after vCPUs are destroyed leads to UAF if the delayed work is processed after vCPUs are destroyed. BUG: KASAN: slab-use-after-free in __kvm_irq_delivery_to_apic_fast+0x9bf/0xa20 arch/x86/kvm/lapic.c:1250 Read of size 8 at addr ffff8880499abea0 by task kworker/1:2/1218 CPU: 1 UID: 0 PID: 1218 Comm: kworker/1:2 Not tainted 7.1.0-rc7 #5 PREEMPT(lazy) Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: events kvm_ioapic_eoi_inject_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 print_report+0x139/0x4ad mm/kasan/report.c:482 kasan_report+0xe4/0x1d0 mm/kasan/report.c:595 __kvm_irq_delivery_to_apic_fast+0x9bf/0xa20 arch/x86/kvm/lapic.c:1250 __kvm_irq_delivery_to_apic+0xd8/0xbf0 arch/x86/kvm/lapic.c:1345 kvm_irq_delivery_to_apic arch/x86/kvm/lapic.h:129 ioapic_service+0x308/0x590 arch/x86/kvm/ioapic.c:492 kvm_ioapic_eoi_inject_work+0x13c/0x190 arch/x86/kvm/ioapic.c:532 process_one_work+0xa59/0x19a0 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 worker_thread+0x5eb/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> Note, the VM is unreachable once kvm_destroy_vm() starts, and scheduling new work via kvm_ioapic_send_eoi() can only be done via KVM_RUN, i.e. requires a live vCPU. Alternatively, KVM could simply destroy the I/O APIC during the "pre" phase of VM destruction, but that gets more than a bit sketchy as KVM expects the I/O APIC to exist if ioapic_in_kernel() is true, and nested virtualization in particular has a bad habit of touching VM-scope state during vCPU destruction. E.g. attempting to free the PIC during the pre phase would lead to a NULL pointer dereference in kvm_cpu_has_extint(), and it's not hard to imagine the I/O APIC having a similar flaw.
How severe is CVE-2026-74517?
CVE-2026-74517 has a CVSS score of 9.3/10 (CRITICAL severity). The EPSS model estimates a 0.13% probability of exploitation in the next 30 days.
How do I fix CVE-2026-74517?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST