# CVE-2021-31930: Cross-site scripting in n/a

> An unauthenticated attacker can inject persistent XSS payloads via registration fields, leading to code execution when privileged users delete the account.

- **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:** 19 May 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-6x7c-5jc6-7qc6

## What is CVE-2021-31930?

CVE-2021-31930 is a medium-severity cross-site scripting vulnerability in n/a, published on 19 May 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

Persistent cross-site scripting (XSS) in the web interface of Concerto through 2.3.6 allows an unauthenticated remote attacker to introduce arbitrary JavaScript by injecting an XSS payload into the First Name or Last Name parameter upon registration. When a privileged user attempts to delete the account, the XSS payload will be executed.

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

## Which versions are affected by CVE-2021-31930?

It affects 1 product.


Products: Concerto-Signage Concerto.

## How do I fix CVE-2021-31930?

No fix has been published for CVE-2021-31930 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-31930 being exploited?

There is no known exploitation of CVE-2021-31930 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31930 and fix it if it is affected.

What it is: CVE-2021-31930 is a medium-severity cross-site scripting vulnerability in n/a, published on 19 May 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-2021-31930 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-2021-31930/ (Markdown: https://insights.sbomify.com/CVE-2021-31930/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31930
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31930
- OSV: https://osv.dev/vulnerability/CVE-2021-31930

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31930/
Summaries are generated and may contain mistakes; the official description above is the record.