CVE-2025-20281

CVE-2025-20281 is an injection flaw (CWE-74) in a specific API of Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC), caused by insufficient validation of user-supplied input. An unauthenticated, remote attacker can trigger it by sending a crafted request to that API; no valid credentials or user interaction are required. A successful exploit yields arbitrary code execution on the underlying operating system with root privileges, giving the attacker full control of the affected device (scope-changing per the CVSS 10.0 score). Any organization running affected ISE or ISE-PIC releases is exposed, particularly where the vulnerable API is reachable from untrusted networks. The flaw is confirmed under active exploitation: CISA added it to the Known Exploited Vulnerabilities catalog on 2025-07-28, EPSS assigns a 97.1% probability of exploitation within 30 days, and ZDI has published a writeup of the unauthenticated root RCE.

What to do: Upgrade Cisco ISE and ISE-PIC to the patched releases specified in Cisco's PSIRT advisory, and check whether the vulnerable API/admin interface is reachable from untrusted networks, restricting access until patching is complete. As a KEV entry added 2025-07-28, U.S. federal agencies must apply vendor mitigations per BOD 22-01 guidance or discontinue use of the product; given EPSS of 97.1% and confirmed active exploitation, prioritize internet-facing ISE instances and review API/web-server logs for signs of exploitation.