# CVE-2016-9318: XML external entity in n/a

> Remote attackers can exploit libxml2's lack of strict file access controls to perform XML External Entity attacks, potentially reading sensitive files or causing denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Nov 2016
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2016-9318, DEBIAN-CVE-2016-9318, ECHO-fe6c-b039-a615, SUSE-SU-2017:0164-1, SUSE-SU-2019:1896-1, UBUNTU-CVE-2016-9318

## What is CVE-2016-9318?

CVE-2016-9318 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 16 Nov 2016. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

libxml2 2.9.4 and earlier, as used in XMLSec 1.2.23 and earlier and other products, does not offer a flag directly indicating that the current document may be read but other files may not be opened, which makes it easier for remote attackers to conduct XML External Entity (XXE) attacks via a crafted document.

Weakness: CWE-611 (Improper Restriction of XML External Entity Reference)

## Which versions are affected by CVE-2016-9318?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libxml2` | SUSE:Linux Enterprise Desktop 12 SP4 | All versions | 2.9.4-46.20.1 |
| `python-libxml2` | SUSE:Linux Enterprise Desktop 12 SP4 | All versions | 2.9.4-46.20.1 |
| `libxml2` | SUSE:Linux Enterprise Server 11 SP4 | All versions | 2.7.6-0.64.1 |
| `libxml2-python` | SUSE:Linux Enterprise Server 11 SP4 | All versions | 2.7.6-0.64.4 |
| `libxml2` | SUSE:Linux Enterprise Server 12 SP4 | All versions | 2.9.4-46.20.1 |
| `python-libxml2` | SUSE:Linux Enterprise Server 12 SP4 | All versions | 2.9.4-46.20.1 |
| `libxml2` | SUSE:Linux Enterprise Server for SAP Applications 11 SP4 | All versions | 2.7.6-0.64.1 |
| `libxml2-python` | SUSE:Linux Enterprise Server for SAP Applications 11 SP4 | All versions | 2.7.6-0.64.4 |
| `libxml2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP4 | All versions | 2.9.4-46.20.1 |
| `python-libxml2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP4 | All versions | 2.9.4-46.20.1 |
| `libxml2` | SUSE:Linux Enterprise Software Development Kit 11 SP4 | All versions | 2.7.6-0.64.1 |
| `libxml2` | SUSE:Linux Enterprise Software Development Kit 12 SP4 | All versions | 2.9.4-46.20.1 |

Products: Canonical Ubuntu Linux, Xmlsoft Libxml2.

## How do I fix CVE-2016-9318?

Upgrade to a fixed version.

## Is CVE-2016-9318 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-9318 exists.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-9318 and fix it if it is affected.

What it is: CVE-2016-9318 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 16 Nov 2016. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-9318 exists.

Affected product: Canonical Ubuntu 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-2016-9318/ (Markdown: https://insights.sbomify.com/CVE-2016-9318/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-9318
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-9318
- OSV: https://osv.dev/vulnerability/CVE-2016-9318

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-9318/
Summaries are generated and may contain mistakes; the official description above is the record.