CVE-2021-1621 Cisco IOS XE Software Interface Queue Wedge Denial of Service Vulnerability

High 7.4 Published 23 Sep 2021 Updated 7 Nov 2024

An unauthenticated adjacent attacker can cause a denial of service by sending specific Layer 2 frames to a Cisco IOS XE router.

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-2021-1621?

CVE-2021-1621 is a high-severity denial of service vulnerability in Cisco Ios Xe, published on 23 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A vulnerability in the Layer 2 punt code of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a queue wedge on an interface that receives specific Layer 2 frames, resulting in a denial of service (DoS) condition. This vulnerability is due to improper handling of certain Layer 2 frames. An attacker could exploit this vulnerability by sending specific Layer 2 frames on the segment the router is connected to. A successful exploit could allow the attacker to cause a queue wedge on the interface, resulting in a DoS condition.

Weakness: CWE-399

Which versions are affected by CVE-2021-1621?

It affects 1 product.

Products include Cisco Ios Xe.

How do I fix CVE-2021-1621?

No fix has been published for CVE-2021-1621 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-2021-1621 being exploited?

There is no known exploitation of CVE-2021-1621 in the wild and no public exploit code.

All Cisco Ios Xe vulnerabilities

Sources

Also known as GHSA-7pgq-9248-43gw.