Rapid7’s 2026 Global Cybersecurity Summit is now available on-demand.Watch sessions.
Rapid7

vulnerability

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

Severity
6
CVSS
(AV:A/AC:L/Au:N/C:N/I:N/A:C)
Published
Sep 9, 2021
Added
Oct 21, 2021
Modified
Dec 21, 2022

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.

Solution

update-xros
Title
Rapid7 Labs

2026 Global Threat Landscape Report

The predictive window has collapsed. Exploitation follows disclosure in days. See how attackers are accelerating and how to stay ahead.