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

> A missing timeout in Linux kernel virtio RTC alarm requests can cause a system hang during device removal, leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90127, DEBIAN-CVE-2026-90127, GHSA-h4vf-f6xj-7ccf, UBUNTU-CVE-2026-90127

## What is CVE-2026-90127?

CVE-2026-90127 is a denial of service vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2026-90127?


## How do I fix CVE-2026-90127?

Apply the vendor's patch.

## Is CVE-2026-90127 being exploited?

There is no known exploitation of CVE-2026-90127 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90127 and fix it if it is affected.

What it is: CVE-2026-90127 is a denial of service vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-90127 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-90127/ (Markdown: https://insights.sbomify.com/CVE-2026-90127/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90127
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90127
- OSV: https://osv.dev/vulnerability/CVE-2026-90127

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90127/
Summaries are generated and may contain mistakes; the official description above is the record.