Is CVE-2016-6406 being actively exploited?

CVE-2016-6406 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2016-6406?

CVE-2016-6406 has a CVSS 3.0 base score of 9.8 (CRITICAL).

CVE-2016-6406

CRITICAL · CVSS 9.8EPSS 3.6%EU EUVD

Cisco IronPort AsyncOS 9.1.2-023, 9.1.2-028, 9.1.2-036, 9.7.2-046, 9.7.2-047, 9.7.2-054, 10.0.0-124, and 10.0.0-125 on Email Security Appliance (ESA) devices, when Enrollment Client before 1.0.2-065 is installed, allows remote attackers to obtain root access via a connection to the testing/debugging interface, aka Bug ID CSCvb26017.

Key facts

CVSS score: 9.8 (v3.0)
Severity: CRITICAL
CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-264
EPSS score: 3.6% (89th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2016-7329)
Published: September 22, 2016
NVD last modified: June 17, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2016-7329 in the EU Vulnerability Database. Last updated in EUVD on August 6, 2024.

View on the EU Vulnerability Database

Affected products

cisco / email security appliance firmware
cisco / email security appliance firmware
cisco / email security appliance firmware
cisco / email security appliance firmware
cisco / email security appliance firmware
cisco / email security appliance firmware
cisco / email security appliance firmware
cisco / email security appliance firmware

Certified products that may be affected

1 FIPS 140 or Common Criteria certified product, from automated matching by sec-certs.org.

Cisco Email Security Appliance v9.1 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10631-2015 - archived

References

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160922-esa(Vendor Advisory)
http://www.securityfocus.com/bid/93116(Third Party Advisory, VDB Entry)
http://www.securitytracker.com/id/1036881

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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