https://www.bleepingcomputer.com/news/security/cisco-vulnerability-lets-attackers-crash-bgp-on-ios-xr-routers/ > Cisco has patched a denial of service (DoS) vulnerability that lets attackers crash the Border Gateway Protocol (BGP) process on IOS XR routers with a single BGP update message. > IOS XR runs on the company's carrier-grade, Network Convergence System (NCS), and Carrier Routing System (CRS) series of routers, such as the ASR 9000, NCS 5500, and 8000 series.