A vulnerability in the IPsec Open API endpoint of Cisco ISE could allow an authenticated, remote attacker to inject arbitrary commands on the underlying operating system.  This vulnerability is due to insufficient validation of user-supplied input in IPsec Open API calls. An attacker could exploit this vulnerability by sending crafted input to the IPsec Open API endpoint on an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system.  To exploit this vulnerability, the attacker must have valid administrative credentials and the node must have more than one network interface, one of which must be configured as an active IPsec tunnel. Note: For CVE-2026-20283, Cisco has assigned a Security Impact Rating (SIR) of High rather than Medium as the score indicates. The reason is that it is easy to get to root from the achieved privilege level.