CVE-2021-34720 Denial of service in Cisco IOS XR Software

High 8.6 Published 9 Sep 2021 Updated 7 Nov 2024

Remote unauthenticated attackers can cause denial of service by exhausting packet memory or crashing the IP SLA process via crafted packets.

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-2021-34720?

CVE-2021-34720 is a high-severity denial of service vulnerability in Cisco Ios Xr, published on 9 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in the IP Service Level Agreements (IP SLA) responder and Two-Way Active Measurement Protocol (TWAMP) features of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause device packet memory to become exhausted or cause the IP SLA process to crash, resulting in a denial of service (DoS) condition. This vulnerability exists because socket creation failures are mishandled during the IP SLA and TWAMP processes. An attacker could exploit this vulnerability by sending specific IP SLA or TWAMP packets to an affected device. A successful exploit could allow the attacker to exhaust the packet memory, which will impact other processes, such as routing protocols, or crash the IP SLA process.

Weakness: CWE-771

Which versions are affected by CVE-2021-34720?

It affects 1 product.

Products include Cisco Ios Xr.

How do I fix CVE-2021-34720?

No fix has been published for CVE-2021-34720 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-2021-34720 being exploited?

There is no known exploitation of CVE-2021-34720 in the wild and no public exploit code.

All Cisco Ios Xr vulnerabilities

Sources

Also known as GHSA-c243-364q-9gwf.