Cisco patches critical CVE-2025-20337 bug in Identity Services Engine with CVSS 10 Severity

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.

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.

CVE-2025-20337 is a critical (CVSS 3.1: 10.0) injection vulnerability (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 submitting a crafted request to the affected API, with no valid credentials required. Successful exploitation allows arbitrary code execution on the underlying operating system with root privileges, giving the attacker full control of the affected device, consistent with the changed-scope, high-impact CVSS score. Any organization running Cisco ISE or ISE-PIC is potentially affected; CISA added the flaw to the Known Exploited Vulnerabilities catalog on 2025-07-28, and press reports indicate active exploitation, including zero-day use per Amazon threat intelligence coverage. EPSS assigns a 67% probability of exploitation within 30 days (99th percentile), and no public proof-of-concept is known.

Do: Upgrade Cisco ISE and ISE-PIC to the fixed releases identified in Cisco's security advisory (fixed version details are not included in this data set), and check management/API logs for unauthenticated crafted API requests indicating exploitation. As an interim mitigation, restrict network access to the affected API and the ISE administration interface. Organizations covered by BOD 22-01 must apply vendor mitigations per Cisco's instructions or discontinue use of the product by the KEV remediation deadline.