# CVE-2013-0339: XML external entity in n/a

> Remote attackers can cause denial of service, read arbitrary files, or send HTTP requests via crafted XML due to improper external entity handling in libxml2.

- **Severity:** Medium 6.8 (`AV:N/AC:M/Au:N/C:P/I:P/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jan 2014
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2013-0339, GHSA-4qgp-72gr-jfg9

## What is CVE-2013-0339?

CVE-2013-0339 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 21 Jan 2014. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libxml2 through 2.9.1 does not properly handle external entities expansion unless an application developer uses the xmlSAX2ResolveEntity or xmlSetExternalEntityLoader function, which allows remote attackers to cause a denial of service (resource consumption), send HTTP requests to intranet servers, or read arbitrary files via a crafted XML document, aka an XML External Entity (XXE) issue.  NOTE: it could be argued that because libxml2 already provides the ability to disable external entity expansion, the responsibility for resolving this issue lies with application developers; according to this argument, this entry should be REJECTed and each affected application would need its own CVE.

Weakness: CWE-264

## Which versions are affected by CVE-2013-0339?

It affects 4 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Suse Linux Enterprise Server, Xmlsoft Libxml2.

## How do I fix CVE-2013-0339?

Apply the vendor's patch.

## Is CVE-2013-0339 being exploited?

There is no known exploitation of CVE-2013-0339 in the wild and no public exploit code.

## 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-2013-0339 and fix it if it is affected.

What it is: CVE-2013-0339 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 21 Jan 2014. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2013-0339 in the wild and no public exploit code.

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-2013-0339/ (Markdown: https://insights.sbomify.com/CVE-2013-0339/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2013-0339
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2013-0339
- OSV: https://osv.dev/vulnerability/CVE-2013-0339

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From sbomify Insights: https://insights.sbomify.com/CVE-2013-0339/
Summaries are generated and may contain mistakes; the official description above is the record.