# CVE-2021-31641: Cross-site scripting in n/a

> Unauthenticated attackers can execute arbitrary scripts via XSS in HTTP 404 responses on multiple CHIYU Technology IoT devices.

- **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:** 1 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-j8pq-98x9-wx56

## What is CVE-2021-31641?

CVE-2021-31641 is a medium-severity cross-site scripting vulnerability in n/a, published on 1 Jun 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 unauthenticated XSS vulnerability exists in several IoT devices from CHIYU Technology, including BF-630, BF-450M, BF-430, BF-431, BF631-W, BF830-W, Webpass, BF-MINI-W, and SEMAC due to a lack of sanitization when the HTTP 404 message is generated.

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

## Which versions are affected by CVE-2021-31641?

It affects 15 products.


Products: Chiyu-Tech Bf-430 Firmware, Chiyu-Tech Bf-431 Firmware, Chiyu-Tech Bf-450m Firmware, Chiyu-Tech Bf-630 Firmware, Chiyu-Tech Bf-631w Firmware, Chiyu-Tech Bf-830w Firmware, Chiyu-Tech Bfminiw Firmware, Chiyu-Tech Semac D1 Firmware, Chiyu-Tech Semac D2 Firmware, Chiyu-Tech Semac D2 N300 Firmware, Chiyu-Tech Semac D4 Firmware, Chiyu-Tech Semac S1 Osdp Firmware, Chiyu-Tech Semac S2 Firmware, Chiyu-Tech Semac S3v3 Firmware, Chiyu-Tech Webpass Firmware.

## How do I fix CVE-2021-31641?

No fix has been published for CVE-2021-31641 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-31641 being exploited?

There is no known exploitation of CVE-2021-31641 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-31251](https://insights.sbomify.com/CVE-2021-31251/): Auth bypass in n/a (critical 9.8)
- [CVE-2021-31249](https://insights.sbomify.com/CVE-2021-31249/): Other in n/a (medium 6.5)
- [CVE-2021-31252](https://insights.sbomify.com/CVE-2021-31252/): Open redirect in n/a (medium 6.1)
- [CVE-2021-31250](https://insights.sbomify.com/CVE-2021-31250/): Cross-site scripting in n/a (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31641 and fix it if it is affected.

What it is: CVE-2021-31641 is a medium-severity cross-site scripting vulnerability in n/a, published on 1 Jun 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-2021-31641 in the wild and no public exploit code.

Affected product: n/a. 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-2021-31641/ (Markdown: https://insights.sbomify.com/CVE-2021-31641/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31641
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31641
- OSV: https://osv.dev/vulnerability/CVE-2021-31641

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31641/
Summaries are generated and may contain mistakes; the official description above is the record.