# CVE-2021-31643: Cross-site scripting in n/a

> Attackers can execute arbitrary scripts via the username parameter in if.cgi on CHIYU Technology IoT devices, potentially compromising user sessions.

- **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:** 1 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-hxrr-8f87-qrgp

## What is CVE-2021-31643?

CVE-2021-31643 is a medium-severity cross-site scripting vulnerability in n/a, published on 1 Jun 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

An XSS vulnerability exists in several IoT devices from CHIYU Technology, including SEMAC, Biosense, BF-630, BF-631, and Webpass due to a lack of sanitization on the component if.cgi - username parameter.

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

## Which versions are affected by CVE-2021-31643?

It affects 11 products.


Products: Chiyu-Tech Bf-630 Firmware, Chiyu-Tech Bf-631 Firmware, Chiyu-Tech Biosense 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-2021-31643?

No fix has been published for CVE-2021-31643 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-31643 being exploited?

There is no known exploitation of CVE-2021-31643 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-31642](https://insights.sbomify.com/CVE-2021-31642/): Integer overflow in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31643 and fix it if it is affected.

What it is: CVE-2021-31643 is a medium-severity cross-site scripting vulnerability in n/a, published on 1 Jun 2021. 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-2021-31643 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-2021-31643/ (Markdown: https://insights.sbomify.com/CVE-2021-31643/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31643
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31643
- OSV: https://osv.dev/vulnerability/CVE-2021-31643

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31643/
Summaries are generated and may contain mistakes; the official description above is the record.