CVE-2017-12228: Cisco IOS

Medium severity, CVSS 5.9. EPSS: 1% chance of exploitation in the next 30 days.

A vulnerability in the Cisco Network Plug and Play application of Cisco IOS 12.4 through 15.6 and Cisco IOS XE 3.3 through 16.4 could allow an unauthenticated, remote attacker to gain unauthorized access to sensitive data by using an invalid certificate. The vulnerability is due to insufficient certificate validation by the affected software. An attacker could exploit this vulnerability by supplying a crafted certificate to an affected device. A successful exploit could allow the attacker to conduct man-in-the-middle attacks to decrypt confidential information on user connections to the affected software. Cisco Bug IDs: CSCvc33171.

Affected products

• Cisco IOS: version 12.4(25e)jao3a only; version 12.4(25e)jao20s only; version 12.4(25e)jap1n only; version 12.4(25e)jap9 only; version 15.0(2)ej only; version 15.0(2)ej1 only; …
• Cisco IOS XE: up to and including 15.4\(3\)s; version 3.3.0xo only; version 3.3.1xo only; version 3.3.2xo only; version 3.5.0e only; version 3.5.1e only; …

Published 2017-09-29. Last modified 2026-06-17.