# CVE-2018-0173: Cisco IOS and IOS XE Software Improper Input Validation Vulnerability

Source: https://junglewise.ai/threats/cve-2018-0173-cisco-ios-and-ios-xe-software-improper-input-validation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-03-03. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2018-0173 · Severity: critical · CVSS 8.6 · Exploited in the wild · Published 2022-03-03

A vulnerability in Cisco IOS and IOS XE Software's DHCPv4 relay function allows an unauthenticated remote attacker to cause a denial-of-service (DoS) via a device reload. The issue stems from improper input validation of encapsulated DHCP Option 82 information in DHCPOFFER messages.

Technologies: [Cisco IOS](https://junglewise.ai/threats/technologies/ios), [Cisco IOS XE](https://junglewise.ai/threats/technologies/ios-xe), [Cisco IOS XE Software](https://junglewise.ai/threats/technologies/ios-xe-software), [Cisco IOS XR](https://junglewise.ai/threats/technologies/ios-xr). Vendors: [Cisco](https://junglewise.ai/threats/vendors/cisco).

## Quick answers

**Is CVE-2018-0173 exploited in the wild?** Yes. CVE-2018-0173 is known to be exploited in the wild, first recorded on 3 March 2022. Treat it as urgent.

**How severe is CVE-2018-0173?** Critical severity, with a CVSS score of 8.6, published 3 March 2022.

**Which products and versions are affected?** Cisco IOS Up to 15.2(6)e0a; Cisco IOS XE Up to 15.2(6)e0a; Cisco IOS Denali 16.3.4; Rockwell Automation Stratix 5400/5410/5700/8000/8300.

**Is there a fix for CVE-2018-0173?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2018-0173 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2018-0173?** Check whether you run Cisco IOS, Cisco IOS XE, Cisco IOS XE Software or one of the others listed. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Cisco IOS Up to 15.2(6)e0a
- Cisco IOS XE Up to 15.2(6)e0a
- Cisco IOS Denali 16.3.4
- Rockwell Automation Stratix 5400/5410/5700/8000/8300

## Timeline

- 2018-03-28: disclosed: Initial Cisco advisory publication
- 2022-03-03: kev added: Added to CISA Known Exploited Vulnerabilities Catalog

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