CVE-2018-0173
Cisco IOS and IOS XE Software Improper Input Validation Vulnerability
What is affected
| Vendor | Cisco |
|---|---|
| Product | IOS and IOS XE Software |
| Weakness | CWE-20 |
The vulnerability
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 can allow for denial-of-service (DoS).
Required action
Apply updates per vendor instructions.
US federal civilian agencies were required to act by 17 March 2022 under BOD 22-01. The deadline is a compliance date, not a measure of severity — it says nothing about how dangerous the flaw is to anyone else.
Where this comes from
Every field on this page is taken from the CISA Known Exploited Vulnerabilities catalog, last synced 11 Nov 2026, 21:30. Nothing here is our own assessment. For the technical scoring, see the NVD record below.
More from Cisco
Cisco BroadWorks
Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability
CVE-2026-76418Cisco Secure Firewall ASA Software and Cisco Secure FTD Software
Cisco Secure Firewall ASA Software and Cisco Secure FTD Software Unchecked Return Value to NULL Pointer Dereference Vulnerability
CVE-2026-76519Cisco Secure Email Gateway
Cisco Secure Email Gateway Relative Path Traversal Vulnerability
CVE-2026-76504Cisco Catalyst SD-WAN Manager
Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability