The vulnerability affects ASR 5000 devices running StarOS and Virtualized Packet Core (VPC) systems. It could allow an attacker to create a denial-of-service (DoS) condition or execute arbitrary code. The company said the problem is due to unsafe code generation by the ASN1C compiler when creating ASN.1 translation functions that are subsequently included within affected Cisco products A malicious actor could exploit the vulnerability by submitting a malicious encoded message that triggers an affected function.”]
Source: https://securityintelligence.com/news/cisco-announces-critical-router-vulnerability/