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

CVE-2018-0172: Technical Deep-Dive (Auto Refreshed)

Generated on 2026-03-31T21:14:45.146Z. This file is automatically regenerated every 30 minutes by the CVE AI enrichment job using web sources (NVD, MITRE, CISA KEV, GitHub).

Executive Technical Summary

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.

Context preserved from previous revision: 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. Notes: Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

Technical Details

CVE: CVE-2018-0172
KEV date added: 2022-03-03
KEV due date: 2022-03-17
NVD published: 2018-03-29
NVD modified: 2026-01-14
MITRE modified: 2026-01-12
CVSS base score: 8.6
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS exploitability score: 3.9
CVSS impact score: 4
Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Changed
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Versions and Products Impacted

cisco / ios
cisco / ios xe
n/a / Cisco IOS and IOS XE (versions: Cisco IOS and IOS XE)

Weakness Classification

CWE-20
CWE-787

Repositories for Lab Validation (Public Examples)

Ostorlab/KEV | stars: 608 | updated: 2026-03-23 | https://github.com/Ostorlab/KEV
Notes: Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

People and Organizations Mentioned

cisco
IOS and IOS XE Software
Ostorlab

Practical Defensive Validation (Authorized Only)

Use only isolated environments and systems you own or are explicitly authorized to test.
Snapshot infrastructure before validation and preserve baseline logs (EDR, SIEM, OS, app).
Inventory cisco / ios assets and confirm exact vulnerable versions with automated checks.
Patch in staged environments and validate closure with scanners + service health checks.
Map detections to MITRE ATT&CK tactics relevant to your environment and tune alert quality.

References

This content is for defensive security training and authorized validation only.