Cisco · IOS XE Software
CVE-2018-0174
Cisco IOS Software and Cisco IOS XE Software Improper Input Validation Vulnerability
What it is
A vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of option 82 information that it receives in DHCP Version 4 (DHCPv4) packets from DHCP relay agents. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuh91645.
CISA: A vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow for denial-of-service (DoS).
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: March 17, 2022
- Added to the CISA list
- March 3, 2022
- Published
- March 28, 2018
- Severity
- High 8.6 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 7.6% in the top 5.5% of all known vulnerabilities
- Weakness
- CWE-20
- More details
- NVD · CVE.org · CISA
All references (6)
- http://www.securityfocus.com/bid/103554
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04
- https://www.tenable.com/security/research/tra-2018-06
- http://www.securitytracker.com/id/1040591
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr3
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05
More exploited flaws from Cisco
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Mar 3, 2022 | Ethernet Virtual Private Network Border Gateway Protocol Denial-of-Service | IOS XE Software | Medium 5.9 | 5.2% |
| Oct 14, 2026 | Relative Path Traversal | Secure Email Gateway | Critical 9.8 | 2.2% |
| Sep 30, 2026 | Hex Encoding | Catalyst SD-WAN Manager | Critical 9.8 | 39% |
| Sep 16, 2026 | Incorrect Use of Privileged APIs | Identity Services Engine | Critical 10.0 | 76% |
| Sep 14, 2026 | SQL Injection | Secure Email Gateway | Critical 9.8 | 30% |
| Sep 9, 2026 | Firewall Management Center Authentication Bypass Using an Alternate Path or Channel | Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management | Critical 10.0 | 88% |
| Aug 11, 2026 | Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection | Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) | High 8.6 | 1.0% |
| Jul 29, 2026 | Secure Firewall Management Center Use of Hard-coded Password | Secure Firewall Management Center (FMC) | Medium 5.3 | 35% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.