CVE-2018-0172: Cisco IOS and IOS XE Software Improper Input Validation Vulnerability

CISA Known Exploited Vulnerabilities

Name

Cisco IOS and IOS XE Software Improper Input Validation Vulnerability

Vendor

Cisco

Product

IOS and IOS XE Software

Added to the catalog

2022-03-03

Due date for US federal agencies

2022-03-17

Weaknesses

CWE-20

Catalog version

2026.10.30

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).

Required action (CISA)

Apply updates per vendor instructions.

Ransomware use: CISA does not mark known use of this vulnerability in ransomware campaigns.

Links in CISA's notes

• https://nvd.nist.gov/vuln/detail/CVE-2018-0172

Read on 2026-11-02T23:39:54.475Z under licence cisa-kev-cc0@b0067899 from https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

NVD analysis

Status

Analyzed

Published

2018-03-28T22:29:01.110

Last modified

2026-06-17T01:29:59.830

Weaknesses

CWE-20, CWE-787

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 a heap overflow condition on the affected device, which will cause the device to reload and result in a DoS condition. Cisco Bug IDs: CSCvg62730.

References

• http://www.securityfocus.com/bid/103552 (Third Party Advisory, VDB Entry)
• http://www.securitytracker.com/id/1040591 (Third Party Advisory, VDB Entry)
• https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04 (Third Party Advisory, US Government Resource)
• https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05 (Third Party Advisory, US Government Resource)
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr1 (Vendor Advisory)
• https://www.tenable.com/security/research/tra-2018-06 (Third Party Advisory)
• http://www.securityfocus.com/bid/103552 (Third Party Advisory, VDB Entry)
• http://www.securitytracker.com/id/1040591 (Third Party Advisory, VDB Entry)
• https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04 (Third Party Advisory, US Government Resource)
• https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05 (Third Party Advisory, US Government Resource)
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr1 (Vendor Advisory)
• https://www.tenable.com/security/research/tra-2018-06 (Third Party Advisory)
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0172 (US Government Resource)

This product uses the NVD API but is not endorsed or certified by the NVD.

Read on 2026-11-02T23:41:35.381Z under licence nvd-api-terms-of-use@ff2a5288 from https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2018-0172

CVE record

Assigner

cisco

State

PUBLISHED

Published

2018-03-28T22:00:00.000Z

Updated

2026-01-12T21:59:22.400Z

Problem types

CWE-20

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 a heap overflow condition on the affected device, which will cause the device to reload and result in a DoS condition. Cisco Bug IDs: CSCvg62730.

References

• https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04
• https://www.tenable.com/security/research/tra-2018-06
• 1040591
• 103552
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr1
• https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05

Read on 2026-11-03T00:36:00.560Z under licence cve-terms-of-use@81bfa2f3 from https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2018/0xxx/CVE-2018-0172.json

Defensive techniques (MITRE D3FEND)

D3FEND maps these defensive techniques to the weakness (CWE) that NVD lists for this CVE, through the digital artifacts the weakness affects. D3FEND does not say they stop this vulnerability.

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