CVE-2023-20027 Cisco IOS XE Software Virtual Fragmentation Reassembly Denial of Service Vulnerability

High 8.6 Published 23 Mar 2023 Updated 28 Oct 2024

Remote attackers can cause device reloads via fragmented packets if Virtual Fragmentation Reassembly is enabled on interfaces with specific MTU settings.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-20027?

CVE-2023-20027 is a high-severity denial of service vulnerability in Cisco Ios Xe, published on 23 Mar 2023. 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 the IPv4 Virtual Fragmentation Reassembly (VFR) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper reassembly of large packets that occurs when VFR is enabled on either a tunnel interface or on a physical interface that is configured with a maximum transmission unit (MTU) greater than 4,615 bytes. An attacker could exploit this vulnerability by sending fragmented packets through a VFR-enabled interface on an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Weakness: CWE-416

Which versions are affected by CVE-2023-20027?

It affects 1 product.

Products include Cisco Ios Xe.

How do I fix CVE-2023-20027?

No fix has been published for CVE-2023-20027 yet. Limit exposure of the affected software until one is available.

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-2023-20027 being exploited?

There is no known exploitation of CVE-2023-20027 in the wild and no public exploit code.

All Cisco Ios Xe vulnerabilities

Sources

Also known as GHSA-w837-qm63-r5ph.