# CVE-2018-20239: Cross-site scripting in Atlassian Application Links

> Remote attackers can inject arbitrary HTML or JavaScript via the applinkStartingUrl parameter in Atlassian Application Links.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 30 Apr 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-778g-4c8j-829w

## What is CVE-2018-20239?

CVE-2018-20239 is a medium-severity cross-site scripting vulnerability in Atlassian Crucible, published on 30 Apr 2019. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Application Links before version 5.0.11, from version 5.1.0 before 5.2.10, from version 5.3.0 before 5.3.6, from version 5.4.0 before 5.4.12, and from version 6.0.0 before 6.0.4 allows remote attackers to inject arbitrary HTML or JavaScript via a cross site scripting (XSS) vulnerability in the applinkStartingUrl parameter. The product is used as a plugin in various Atlassian products where the following are affected: Confluence before version 6.15.2, Crucible before version 4.7.0, Crowd before version 3.4.3, Fisheye before version 4.7.0, Jira before version 7.13.3 and 8.x before 8.1.0.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2018-20239?

It affects 8 products.


Products: Atlassian Application Links, Atlassian Confluence Data Center, Atlassian Confluence Server, Atlassian Crowd, Atlassian Crucible, Atlassian Fisheye, Atlassian Jira Data Center, Atlassian Jira Server.

## How do I fix CVE-2018-20239?

No fix has been published for CVE-2018-20239 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-20239 being exploited?

There is no known exploitation of CVE-2018-20239 in the wild and no public exploit code.

## Other vulnerabilities in Atlassian Crucible

- [CVE-2017-18111](https://insights.sbomify.com/CVE-2017-18111/): XML external entity in Application Links (high 8.7)
- [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-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-2018-20239 and fix it if it is affected.

What it is: CVE-2018-20239 is a medium-severity cross-site scripting vulnerability in Atlassian Crucible, published on 30 Apr 2019. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-20239 in the wild and no public exploit code.

Affected product: Atlassian Crucible. 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-2018-20239/ (Markdown: https://insights.sbomify.com/CVE-2018-20239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20239
- OSV: https://osv.dev/vulnerability/CVE-2018-20239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20239/
Summaries are generated and may contain mistakes; the official description above is the record.