# CVE-2026-62427: sysctl and platform-op locks open to abuse

> Attackers can cause denial of service in Xen hypervisor by abusing unfair system-wide locks in platform operations, potentially blocking legitimate system management tasks.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** ALPINE-CVE-2026-62427, DEBIAN-CVE-2026-62427, GHSA-92vf-cq3f-7mp6, UBUNTU-CVE-2026-62427

## What is CVE-2026-62427?

CVE-2026-62427 is a high-severity denial of service vulnerability in Xen, published on 28 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

[This CNA information record relates to multiple CVEs; the
text explains which aspects/vulnerabilities correspond to which CVE.]

To manage the system, sysctl and platform operations are used by the
control domain or a possible Xenstore domain.  Some of these operations
may not be executed in parallel, so a system-wide lock each is used.
The way those locks are acquired is, however, not providing any fairness.
Furthermore, with XSM/Flask in use, the lock acquire will, for some
operations, occur ahead of any permission checking.

The sysctl issue is CVE-2026-62426.

The platform-op issue is CVE-2026-62427.

Weakness: CWE-305 (Authentication Bypass by Primary Weakness), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2026-62427?


## How do I fix CVE-2026-62427?

Apply the vendor's patch.

## Is CVE-2026-62427 being exploited?

There is no known exploitation of CVE-2026-62427 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62427 and fix it if it is affected.

What it is: CVE-2026-62427 is a high-severity denial of service vulnerability in Xen, published on 28 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-62427 in the wild and no public exploit code.

Affected product: Xen. 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-2026-62427/ (Markdown: https://insights.sbomify.com/CVE-2026-62427/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62427
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62427
- OSV: https://osv.dev/vulnerability/CVE-2026-62427

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62427/
Summaries are generated and may contain mistakes; the official description above is the record.