CVE-2018-0173
Cisco IOS and IOS XE
Published 28 Mar 2018 · updated 17 Jun 2026 · Analyzed
Exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on 3 Mar 2022, with a remediation deadline of 17 Mar 2022 for US federal agencies.
Required action: Apply updates per vendor instructions.
Description
A vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in DHCP Version 4 (DHCPv4) packets could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a Relay Reply denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of encapsulated option 82 information that it receives in DHCPOFFER messages from DHCPv4 servers. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device, which the device would then forward to a DHCPv4 server. When the affected software processes the option 82 information that is encapsulated in the response from the server, an error could occur. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvg62754.
References
- www.securityfocus.com/bid/103545 · Broken Link, Third Party Advisory, VDB Entry
- www.securitytracker.com/id/1040591 · Broken Link, Third Party Advisory, VDB Entry
- ics-cert.us-cert.gov/advisories/ICSA-18-107-04 · Third Party Advisory, US Government Resource
- ics-cert.us-cert.gov/advisories/ICSA-18-107-05 · Third Party Advisory, US Government Resource
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr2 · Vendor Advisory
- www.tenable.com/security/research/tra-2018-06 · Third Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0173 · US Government Resource