SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-0421

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.

HIGH 8.6EPSS 3.48%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (3.48%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.0
8.6 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS
3.48% probability · 89th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-399, CWE-772
Affected
cisco/prime access registrar · cisco/prime access registrar jumpstart
Source
psirt@cisco.com
EPSS trend
0%3%5%27 October 2026: 3.48%27 October 202627 October 2026

EPSS 3.5% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.