CVE-2026-90127: virtio: rtc: time out alarm requests

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: virtio: rtc: time out alarm requests RTC class operations run with rtc_device.ops_lock held. The virtio RTC alarm requests currently wait without a timeout for the device to return their requestq buffers. On surprise removal, virtio-pci marks the virtqueues broken before unregistering the virtio device. If an alarm request is waiting when the device stops responding, viortc_remove() blocks in viortc_class_stop() while trying to acquire ops_lock. The request cannot complete and device removal hangs until the waiting task is signalled. Use the same 60-second timeout as clock read requests for alarm reads, alarm programming, and alarm interrupt enable requests. The existing message reference counting keeps a timed-out request alive until a late response or device teardown.

Affected products

Linux kernel: 6.16 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

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