CVE-2018-0197

A vulnerability in the VLAN Trunking Protocol (VTP) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to corrupt the internal VTP database on an affected device and cause a denial of service (DoS) condition. The vulnerability is due to a logic error in how the affected software handles a subset of VTP packets. An attacker could exploit this vulnerability by sending VTP packets in a sequence that triggers a timeout in the VTP message processing code of the affected software. A successful exploit could allow the attacker to impact the ability to create, modify, or delete VLANs and cause a DoS condition. There are workarounds that address this vulnerability. This vulnerability affects Cisco devices that are running a vulnerable release of Cisco IOS Software or Cisco IOS XE Software, are operating in VTP client mode or VTP server mode, and do not have a VTP domain name configured. The default configuration for Cisco devices that are running Cisco IOS Software or Cisco IOS XE Software and support VTP is to operate in VTP server mode with no domain name configured.

• CWE-20
• CWE-20

• http://www.securityfocus.com/bid/105424Third Party Advisory, VDB Entry
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180926-vtpVendor Advisory
• http://www.securityfocus.com/bid/105424Third Party Advisory, VDB Entry
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180926-vtpVendor Advisory

Published

Oct 5, 2018

Last Modified

Jun 17, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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