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CVE-2018-0159

High 7.5 Exploited in the wild (KEV)

Confirmed active exploitation — CISA KEV catalog

Name
Cisco IOS and XE Software Internet Key Exchange Version 1 Denial-of-Service Vulnerability
Added to catalog
Remediation due date (US federal)
Required action
Apply updates per vendor instructions.

Description

A vulnerability in the implementation of Internet Key Exchange Version 1 (IKEv1) functionality in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of specific IKEv1 packets. An attacker could exploit this vulnerability by sending crafted IKEv1 packets to an affected device during an IKE negotiation. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuj73916.

Metrics

CVSS 3.1
7.5 (HIGH) Score source: NVD CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS — exploit probability
7% (percentile: 94) as of 1 November 2026
CWE
CWE-20

Affected products

cisco: ios; cisco: asr 901-12c-f-d; cisco: asr 901-12c-ft-d; cisco: asr 901-4c-f-d; cisco: asr 901-4c-ft-d; cisco: asr 901-6cz-f-a; cisco: asr 901-6cz-f-d; cisco: asr 901-6cz-ft-a; cisco: asr 901-6cz-ft-d; cisco: me 3600x-24cx-m; cisco: me 3600x-24fs-m; cisco: me 3600x-24ts-m; cisco: me 3800x-24fs-m; cisco: ios xe

References