# CVE-2021-3830: Cross-site Scripting (XSS) - Stored in btcpayserver/btcpayserver

> Stored XSS in BTCPay Server allows attackers to inject malicious scripts, potentially leading to session hijacking or code execution.

- **Severity:** Low 3.8 (`CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Sep 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-3xmg-w8wr-4536

## What is CVE-2021-3830?

CVE-2021-3830 is a low-severity cross-site scripting vulnerability in btcpayserver/btcpayserver, published on 26 Sep 2021. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

btcpayserver is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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

## Which versions are affected by CVE-2021-3830?

It affects 1 product.


Products: Btcpayserver Btcpay Server.

## How do I fix CVE-2021-3830?

No fix has been published for CVE-2021-3830 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3830 being exploited?

There is no known exploitation of CVE-2021-3830 in the wild and no public exploit code.

## Other vulnerabilities in btcpayserver/btcpayserver

- [CVE-2022-32984](https://insights.sbomify.com/CVE-2022-32984/): Information disclosure in n/a (high 7.5)
- [CVE-2021-29249](https://insights.sbomify.com/CVE-2021-29249/): Information disclosure in n/a (high 7.5)
- [CVE-2021-29246](https://insights.sbomify.com/CVE-2021-29246/): Path traversal in n/a (medium 6.7)
- [CVE-2021-29251](https://insights.sbomify.com/CVE-2021-29251/): Missing authorization in n/a (medium 6.5)
- [CVE-2023-0879](https://insights.sbomify.com/CVE-2023-0879/): Cross-site Scripting (XSS) - Stored in btcpayserver/btcpayserver (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3830 and fix it if it is affected.

What it is: CVE-2021-3830 is a low-severity cross-site scripting vulnerability in btcpayserver/btcpayserver, published on 26 Sep 2021. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3830 in the wild and no public exploit code.

Affected product: btcpayserver/btcpayserver. 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-2021-3830/ (Markdown: https://insights.sbomify.com/CVE-2021-3830/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3830
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3830
- OSV: https://osv.dev/vulnerability/CVE-2021-3830

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3830/
Summaries are generated and may contain mistakes; the official description above is the record.