CVE-2021-27657
No exploitation reported by the sources we read.
- Published2021-06-04
- WeaknessCWE-269
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTC- 2021-06-0415:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-27657?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-27657?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 11.0 | ≤ 11.0 | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
Johnson Controls Metasys
Metasys: All versions
Fix
- Vendor fix CISA ICSA-21-159-01 · 1 productDelete any user accounts if the user is no longer with the company or have been reassigned to another position where they no longer need to use Metasys.
- Vendor fix CISA ICSA-21-159-01 · 1 productMonitor the audit logs as well as the Cyber Health Dashboard if the site has a Metasys Server at Release 10.1 or later to monitor user activity.
- Vendor fix CISA ICSA-21-159-01 · 1 productEnforce a password change across the Metasys site on a regular basis.
- Mitigation from the vendor CISA ICSA-21-159-01 · 1 productJohnson Controls recommends that users of versions earlier than 9.0 upgrade to a supported release. Users of Version 9.0 (engine), 10.0, 10.1, or 11.0 are recommended to install the patch.
- Mitigation from the vendor CISA ICSA-21-159-01 · 1 productReview all user accounts that are active or dormant and determine if they are still required through the Dormant User feature.
- Mitigation from the vendor CISA ICSA-21-159-01 · 1 productPlease see Johnson Controls product security advisory number JCI-PSA-2021-05 for additional information.
Advisories and patches
- www.johnsoncontrols.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Published
- 2021-06-04
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-27657?
Is CVE-2021-27657 actively exploited?
What is the CVSS score for CVE-2021-27657?
Running Johnson Controls Metasys? Hear about its next vulnerability
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
- Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.
Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.