CVE-2024-20312 Null dereference in Cisco IOS XE Software

High 7.4 Published 27 Mar 2024 Updated 26 Aug 2025

An adjacent attacker can cause a denial of service on Cisco IOS devices by sending crafted IS-IS packets after forming an adjacency.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2024-20312?

CVE-2024-20312 is a high-severity vulnerability in Cisco Ios, published on 27 Mar 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and have formed an adjacency.

Weakness: CWE-476

Which versions are affected by CVE-2024-20312?

It affects 2 products.

Products include Cisco Ios, Cisco Ios Xe.

How do I fix CVE-2024-20312?

No fix has been published for CVE-2024-20312 yet. Limit exposure of the affected software until one is available.

Is CVE-2024-20312 being exploited?

There is no known exploitation of CVE-2024-20312 in the wild and no public exploit code.

All Cisco Ios vulnerabilities

Sources

Also known as GHSA-h59x-f52x-4wxj.