CVE-2016-6393

Name: CVE-2016-6393
Creator: NVD / NIST
Published: 2016-10-05T20:59:07.853+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 4.60%

Last modified Jun 17, 2026

CVE-2016-6393 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. The AAA service in Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 2.1 through 3.18 and 16.2 allows remote attackers to cause a denial of service (device reload) via a failed SSH connection attempt that is mishandled during generation of an error-log message, aka Bug ID CSCuy87667.. EPSS estimates a 4.60% chance of exploitation in the next 30 days.

Description

The AAA service in Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 2.1 through 3.18 and 16.2 allows remote attackers to cause a denial of service (device reload) via a failed SSH connection attempt that is mishandled during generation of an error-log message, aka Bug ID CSCuy87667.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

4.60%

90.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-399

Affected Software

Vendor	Product	Versions
Cisco	Ios	>= 12.0, <= 12.4
Cisco	Ios	>= 15.0, <= 15.6
Cisco	Ios Xe	>= 2.1.0, <= 3.18.0
Cisco	Ios Xe	16.2

References

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-aaadosVendor Advisory
http://www.securityfocus.com/bid/93196Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1036914Third Party Advisory, VDB Entry
https://ics-cert.us-cert.gov/advisories/ICSA-16-287-04Third Party Advisory, US Government Resource
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-aaadosVendor Advisory
http://www.securityfocus.com/bid/93196Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1036914Third Party Advisory, VDB Entry
https://ics-cert.us-cert.gov/advisories/ICSA-16-287-04Third Party Advisory, US Government Resource

Timeline

Published: Oct 5, 2016
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2016-6393?

How severe is CVE-2016-6393?

CVE-2016-6393 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 4.60% probability of exploitation in the next 30 days.

How do I fix CVE-2016-6393?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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Source: NVD / NIST