{"cve":"CVE-2021-27657","nvd":{"published":"2021-06-04T15:15:07.517","modified":"2026-06-17T03:45:18.450","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-269"],"references":["https://us-cert.cisa.gov/ics/advisories/icsa-21-159-01","https://us-cert.gov/ics/advisories","https://www.johnsoncontrols.com/cyber-solutions/security-advisories","https://us-cert.cisa.gov/ics/advisories/icsa-21-159-01","https://us-cert.gov/ics/advisories"],"products":["johnsoncontrols:metasys"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-27657","score":0.01245,"percentile":0.69297,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}