# CVE-2017-20239: MDwiki Cross-Site Scripting via Location Hash Parameter

> Remote attackers can execute arbitrary JavaScript in victims' browsers by injecting malicious code into the location hash parameter of MDwiki.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 Apr 2026
- **Updated:** 1 Oct 2026
- **Also known as:** GHSA-gp82-mmj7-m5w2

## What is CVE-2017-20239?

CVE-2017-20239 is a medium-severity cross-site scripting vulnerability in Dynalon MDwiki, published on 12 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

MDwiki contains a cross-site scripting vulnerability that allows remote attackers to execute arbitrary JavaScript by injecting malicious code through the location hash parameter. Attackers can craft URLs with JavaScript payloads in the hash fragment that are parsed and rendered without sanitization, causing the injected scripts to execute in the victim's browser context.

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

## Which versions are affected by CVE-2017-20239?

It affects 1 product.


Products: Dynalon Mdwiki.

## How do I fix CVE-2017-20239?

No fix has been published for CVE-2017-20239 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-20239 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-20239 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-20239 and fix it if it is affected.

What it is: CVE-2017-20239 is a medium-severity cross-site scripting vulnerability in Dynalon MDwiki, published on 12 Apr 2026. An attacker can exploit it over the internet without logging in, 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-2017-20239 exists.

Affected product: Dynalon MDwiki. 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-2017-20239/ (Markdown: https://insights.sbomify.com/CVE-2017-20239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-20239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-20239
- OSV: https://osv.dev/vulnerability/CVE-2017-20239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-20239/
Summaries are generated and may contain mistakes; the official description above is the record.