# CVE-2017-18111: XML external entity in Application Links

> An XXE vulnerability in Atlassian Application Links allows attackers to read internal files, probe network resources, and cause denial of service.

- **Severity:** High 8.7 (`CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Mar 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-9563-9277-f9w9

## What is CVE-2017-18111?

CVE-2017-18111 is a high-severity vulnerability in Atlassian Application Links, published on 29 Mar 2019. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

The OAuthHelper in Atlassian Application Links before version 5.0.10, from version 5.1.0 before version 5.1.3, and from version 5.2.0 before version 5.2.6 used an XML document builder that was vulnerable to XXE when consuming a client OAuth request. This allowed malicious oauth application linked applications to probe internal network resources by requesting internal locations, read the contents of files and also cause an out of memory exception affecting availability via an XML External Entity vulnerability.

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

## Which versions are affected by CVE-2017-18111?

It affects 1 product.


Products: Atlassian Application Links.

## How do I fix CVE-2017-18111?

No fix has been published for CVE-2017-18111 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-18111 being exploited?

There is no known exploitation of CVE-2017-18111 in the wild and no public exploit code.

## Other vulnerabilities in Atlassian Application Links

- [CVE-2017-18096](https://insights.sbomify.com/CVE-2017-18096/): Server-side request forgery in Atlassian Application Links (high 7.2)
- [CVE-2017-16860](https://insights.sbomify.com/CVE-2017-16860/): Cross-site scripting in Application Links (medium 6.1)
- [CVE-2018-20239](https://insights.sbomify.com/CVE-2018-20239/): Cross-site scripting in Atlassian Application Links (medium 5.4)
- [CVE-2019-20105](https://insights.sbomify.com/CVE-2019-20105/): Missing authorization in Application Links (medium 4.9)
- [CVE-2018-5227](https://insights.sbomify.com/CVE-2018-5227/): Cross-site scripting in Atlassian Application Links (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-18111 and fix it if it is affected.

What it is: CVE-2017-18111 is a high-severity vulnerability in Atlassian Application Links, published on 29 Mar 2019. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-18111 in the wild and no public exploit code.

Affected product: Atlassian Application Links. 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-2017-18111/ (Markdown: https://insights.sbomify.com/CVE-2017-18111/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-18111
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-18111
- OSV: https://osv.dev/vulnerability/CVE-2017-18111

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-18111/
Summaries are generated and may contain mistakes; the official description above is the record.