CVE-2018-0421: Cisco Prime Access Registrar Denial of Service Vulnerability

Severity: high (CVSS 8.6 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-10-05 · updated 2026-06-17
Weakness: CWE-399

Description

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

How to fix

Upgrade to a fixed version: Cisco Prime Access Registrar 7.3.0.4, 8.0.1.1; Cisco Prime Access Registrar Jumpstart 7.3.0.4, 8.0.1.1. Check the vendor advisory for mitigations.

References

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