# CVE-2020-13697: NanoHTTPD Cross-site Scripting vulnerability

> Reflected XSS in NanoHTTPD allows attackers to execute arbitrary scripts in victims' browsers via unsanitized query string input in the default GET handler.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A: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:** 23 Feb 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-pr5m-4w22-8483

## What is CVE-2020-13697?

CVE-2020-13697 is a medium-severity cross-site scripting vulnerability in n/a, published on 23 Feb 2021. 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

An issue was discovered in RouterNanoHTTPD.java in NanoHTTPD through 2.3.1. The GeneralHandler class implements a basic GET handler that prints debug information as an HTML page. Any web server that extends this class without implementing its own GET handler is vulnerable to reflected XSS, because the GeneralHandler GET handler prints user input passed through the query string without any sanitization.

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

## Which versions are affected by CVE-2020-13697?

2 open source packages ship an affected version, including org.nanohttpd:nanohttpd-nanolets. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.nanohttpd:nanohttpd-nanolets` | Maven | All versions to 2.3.1 | None |
| `org.nanohttpd:nanohttpd-nanolets` | Maven | All versions to 2.3.1 | None |

Products: Nanohttpd Nanohttpd.

## How do I fix CVE-2020-13697?

No fix has been published for CVE-2020-13697 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-13697 being exploited?

There is no known exploitation of CVE-2020-13697 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2022-21230](https://insights.sbomify.com/CVE-2022-21230/): Information Exposure (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-13697 and fix it if it is affected.

What it is: CVE-2020-13697 is a medium-severity cross-site scripting vulnerability in n/a, published on 23 Feb 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-13697 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.nanohttpd:nanohttpd-nanolets (Maven): affected all versions up to 2.3.1; no fix listed
- org.nanohttpd:nanohttpd-nanolets (Maven): affected all versions up to 2.3.1; no fix listed

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-2020-13697/ (Markdown: https://insights.sbomify.com/CVE-2020-13697/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-13697
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-13697
- OSV: https://osv.dev/vulnerability/CVE-2020-13697

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-13697/
Summaries are generated and may contain mistakes; the official description above is the record.