# CVE-2016-9637: Privilege escalation in n/a

> Local guest administrators can escalate privileges to the qemu process via out-of-range ioport access in Xen with qemu device model.

- **Severity:** High 7.5 (`CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Feb 2017
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-9637, GHSA-5m8h-4qv2-6hhp, RHSA-2016:2963, UBUNTU-CVE-2016-9637

## What is CVE-2016-9637?

CVE-2016-9637 is a high-severity vulnerability in Citrix Xenserver, published on 16 Feb 2017. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The (1) ioport_read and (2) ioport_write functions in Xen, when qemu is used as a device model within Xen, might allow local x86 HVM guest OS administrators to gain qemu process privileges via vectors involving an out-of-range ioport access.

Weakness: CWE-264

## Which versions are affected by CVE-2016-9637?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `xen` | Red Hat:enterprise_linux:5::client | All versions | 0:3.0.3-148.el5_11 |
| `xen-debuginfo` | Red Hat:enterprise_linux:5::client | All versions | 0:3.0.3-148.el5_11 |
| `xen-libs` | Red Hat:enterprise_linux:5::client | All versions | 0:3.0.3-148.el5_11 |
| `xen` | Red Hat:enterprise_linux:5::server | All versions | 0:3.0.3-148.el5_11 |
| `xen-debuginfo` | Red Hat:enterprise_linux:5::server | All versions | 0:3.0.3-148.el5_11 |
| `xen-libs` | Red Hat:enterprise_linux:5::server | All versions | 0:3.0.3-148.el5_11 |
| `xen` | Red Hat:rhel_virtualization:5::client | All versions | 0:3.0.3-148.el5_11 |
| `xen-debuginfo` | Red Hat:rhel_virtualization:5::client | All versions | 0:3.0.3-148.el5_11 |
| `xen-devel` | Red Hat:rhel_virtualization:5::client | All versions | 0:3.0.3-148.el5_11 |
| `xen` | Red Hat:rhel_virtualization:5::server | All versions | 0:3.0.3-148.el5_11 |
| `xen-debuginfo` | Red Hat:rhel_virtualization:5::server | All versions | 0:3.0.3-148.el5_11 |
| `xen-devel` | Red Hat:rhel_virtualization:5::server | All versions | 0:3.0.3-148.el5_11 |

Products: Citrix Xenserver.

## How do I fix CVE-2016-9637?

Apply the vendor's patch.

## Is CVE-2016-9637 being exploited?

There is no known exploitation of CVE-2016-9637 in the wild and no public exploit code.

## Other vulnerabilities in Citrix Xenserver

- [CVE-2014-4947](https://insights.sbomify.com/CVE-2014-4947/): Memory corruption in n/a (critical 10.0)
- [CVE-2018-14007](https://insights.sbomify.com/CVE-2018-14007/): Path traversal in n/a (critical 9.8)
- [CVE-2015-7705](https://insights.sbomify.com/CVE-2015-7705/): Denial of service in n/a (critical 9.8)
- [CVE-2016-5302](https://insights.sbomify.com/CVE-2016-5302/): Auth bypass in n/a (critical 9.8)
- [CVE-2017-12134](https://insights.sbomify.com/CVE-2017-12134/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-9637 and fix it if it is affected.

What it is: CVE-2016-9637 is a high-severity vulnerability in Citrix Xenserver, published on 16 Feb 2017. 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-2016-9637 in the wild and no public exploit code.

Affected product: Citrix Xenserver. 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-2016-9637/ (Markdown: https://insights.sbomify.com/CVE-2016-9637/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-9637
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-9637
- OSV: https://osv.dev/vulnerability/CVE-2016-9637

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-9637/
Summaries are generated and may contain mistakes; the official description above is the record.