What is CVE-2016-6398?

CVE-2016-6398 is a medium-severity vulnerability in Cisco iOS, classified under Information Disclosure. CVSS score: 5.3/10. Published 2016-09-12.

How severe is CVE-2016-6398?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Information disclosure in Cisco iOS

CVE-2016-6398

The PPTP server in Cisco IOS 15.5(3)M does not properly initialize packet buffers, which allows remote attackers to obtain sensitive information from earlier network communication by reading packet data, aka Bug ID CSCvb16274.

Vulnerability class: Information Disclosure

Published 2016-09-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.013 (68.6th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 68.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: 0.000

Affected products

Cisco iOS — versions 15.5(3)m, 15.5\(3\)m

Weakness classification (CWE)

CWE-200 — Information Disclosure

References

www.securityfocus.com/bid/92734 (vdb-entry)
www.securitytracker.com/id/1036732 (vdb-entry)
tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160902… (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2016-6398?: CVE-2016-6398 is a medium-severity vulnerability in Cisco iOS, classified under Information Disclosure. CVSS score: 5.3/10. Published 2016-09-12.
How severe is CVE-2016-6398?: Medium severity. CVSS v3 base score is 5.3 out of 10.