CVE-2026-97986: virtio_input: stop callbacks before unregistering input device
In the Linux kernel, the following vulnerability has been resolved:
virtioinput: stop callbacks before unregistering input device
virtinputremove() unregisters the input device before resetting the virtio device. virtinputrecvevents() drops vi->lock around inputevent(), so clearing vi->ready does not stop a callback that passed the entry check. It can still use vi->idev, requeue buffers and kick the queue.
Reset first, as virtinputfreeze() already does. With the preceding core change, reset waits for callbacks before inputunregisterdevice() can free vi->idev. Recheck vi->ready after taking the lock again: keep draining completed events so an input packet is not truncated, but stop requeueing buffers and kicking the queue.
With evdev attached, inputunregisterhandle() currently waits for an RCU grace period, which also waits out IRQ callbacks. This masks the lifetime bug on PCI and MMIO, but does not protect sleepable callbacks on other transports.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.158.1-1 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.190-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
Upgrade
debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
In virtio_input, reset the virtio device and stop callbacks before unregistering the input device; after rechecking vi->ready under the lock, continue draining completed events but stop requeueing buffers and kicking the queue.
Event History
Frequently Asked Questions
Which systems are most likely exposed to this issue?
Systems using the Linux kernel virtio input driver are affected when the virtio input device is removed while event-receive callbacks may still run. PCI and MMIO transports may have the issue masked by an RCU grace period when evdev is attached, but that does not protect sleepable callbacks on other transports.
What condition is required to trigger the lifetime issue?
The virtio input device must be unregistered while a receive-events callback has already passed its readiness check. Because the callback drops the driver lock around input event delivery, it can later continue using the input device and requeue or kick virtio buffers after device teardown begins.
What is the relevant remediation behavior?
The fix resets the virtio device before unregistering the input device, so reset waits for active callbacks before the input device can be freed. It also rechecks readiness after reacquiring the lock, allowing completed events to drain while preventing buffer requeueing and queue kicks during teardown.