All Cisco IOS XR routers affected (if multicast routing is enabled)
https://www.bleepingcomputer.com/news/security/cisco-warns-of-actively-exploited-bugs-in-carrier-grade-routers/
09/01/20 Update below. This post was originally published on August 31st, 2020. We updated it to reflect that there are two actively exploited DVMRP Memory Exhaustion Vulnerabilities according to Cisco's updated security advisory.
Cisco warned over the weekend that threat actors are trying to exploit two high severity memory exhaustion denial-of-service (DoS) vulnerabilities in the company's Cisco IOS XR software that runs on carrier-grade routers.