CVE-2021-34713 Cisco IOS XR Software for ASR 9000 Series Routers Denial of Service Vulnerability

High 7.4 Published 9 Sep 2021 Updated 7 Nov 2024

An unauthenticated adjacent attacker can cause a line card reboot on Cisco ASR 9000 routers by sending specific Ethernet frames, resulting in a denial of service.

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-2021-34713?

CVE-2021-34713 is a high-severity denial of service vulnerability in Cisco Ios Xr, published on 9 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 XR Software running on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to cause the affected line card to reboot. This vulnerability is due to incorrect handling of specific Ethernet frames that cause a spin loop that can make the network processors unresponsive. An attacker could exploit this vulnerability by sending specific types of Ethernet frames on the segment where the affected line cards are attached. A successful exploit could allow the attacker to cause the affected line card to reboot.

Weakness: CWE-399

Which versions are affected by CVE-2021-34713?

It affects 1 product.

Products include Cisco Ios Xr.

How do I fix CVE-2021-34713?

No fix has been published for CVE-2021-34713 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-2021-34713 being exploited?

There is no known exploitation of CVE-2021-34713 in the wild and no public exploit code.

All Cisco Ios Xr vulnerabilities

Sources

Also known as GHSA-ggcm-cr9q-hv99.