CVE-2018-0421: Cisco Prime Access Registrar

High severity, CVSS 8.6. EPSS: 3.5% chance of exploitation in the next 30 days.

A vulnerability in TCP connection management in Cisco Prime Access Registrar could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition when the application unexpectedly restarts. The vulnerability is due to incorrect handling of incoming TCP SYN packets to specific listening ports. The improper handling of the TCP SYN packets could cause a system file description to be allocated and not freed. An attacker could exploit this vulnerability by sending a crafted stream of TCP SYN packets to the application. A successful exploit could allow the attacker to cause the application to eventually restart if a file description cannot be obtained.

Affected products

• Cisco Prime Access Registrar: from 7.3, before 7.3.0.4 (fixed in 7.3.0.4); from 8.0, before 8.0.1.1 (fixed in 8.0.1.1)
• Cisco Prime Access Registrar Jumpstart: from 7.3, before 7.3.0.4 (fixed in 7.3.0.4); from 8.0, before 8.0.1.1 (fixed in 8.0.1.1)

Published 2018-10-05. Last modified 2026-06-17.