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Fencer Vulns
high 8.8

CVE-2021-27661 json

Facility Explorer

published 2021-07-01 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-14407

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

Successful exploitation of this vulnerability could give an authenticated Facility Explorer SNC Series Supervisory Controller (F4-SNC) user an unintended level of access to the controller’s file system, allowing them to access or modify system files by sending specifically crafted web messages to the F4-SNC.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-182-01 updated cvss 8.8

Johnson Controls Facility Explorer

  • Johnson Controls Inc Facility Explorer SNC Series Supervisory Controller 11
    affected: vendor fix, mitigation “For more detailed mitigation instructions, please see Johnson Controls Product Security Advisory JCI-PSA-2021-11 v1”

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

0.82% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

  • Johnson Controls Facility Explorer SNC Series Supervisory Controllers (F4-SNC)

Classification

Weakness
  • CWE-269 Improper Privilege Management
  • CWE-863 Incorrect Authorization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.