CVE-2018-0159 Cisco IOS and XE Software Internet Key Exchange Version 1 Denial-of-Service

Exploited in the wild High 7.5 Published 28 Mar 2018 Updated 12 Jan 2026

Remote attackers can crash Cisco IOS devices by sending crafted IKEv1 packets, causing a denial of service.

Exploited in the wild: Since 3 Mar 2022
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2018-0159?

CVE-2018-0159 is a high-severity denial of service vulnerability in Cisco Ios, published on 28 Mar 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-20

Which versions are affected by CVE-2018-0159?

It affects 2 products.

Products include Cisco Ios, Cisco Ios Xe.

How do I fix CVE-2018-0159?

No fix has been published for CVE-2018-0159 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 17 Mar 2022.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2018-0159 being exploited?

Yes. Attackers have exploited CVE-2018-0159 in the wild since at least 3 Mar 2022.

All Cisco Ios vulnerabilities

Sources

Also known as GHSA-p7j7-5cqq-j6m7.