Cisco IOS XR Software Broadband Network Gateway PPP over Ethernet Denial of Service Vulnerability [CVE-2022-20849]

A vulnerability in the Broadband Network Gateway PPP over Ethernet (PPPoE) feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the PPPoE process to continually crash.

This vulnerability exists because the PPPoE feature does not properly handle an error condition within a specific crafted packet sequence. An attacker could exploit this vulnerability by sending a sequence of specific PPPoE packets from controlled customer premises equipment (CPE). A successful exploit could allow the attacker to cause the PPPoE process to continually restart, resulting in a denial of service condition (DoS).

Cisco has released software updates that address this vulnerability.

There are no workarounds that address this vulnerability.

Vulnerable Products

At the time of publication, this vulnerability affected the following Cisco products if they had the Broadband Network Gateway PPPoE enabled and were running a vulnerable release of Cisco IOS XR Software:

• ASR 9000 Series Aggregation Services Routers
• IOS XRv 9000 Routers

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-bng-Gmg5Gxt