CVE-2026-20237: Cisco Identity Services Engine Software

Critical severity, CVSS 9.1. EPSS: 0.3% chance of exploitation in the next 30 days.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC), engineering teams have conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20237 are related to improper input validation issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-20.

Affected products

• Cisco Cisco Identity Services Engine Software: version 3.1.0 only; version 3.1.0 p1 only; version 3.1.0 p3 only; version 3.1.0 p2 only; version 3.2.0 only; version 3.1.0 p4 only; …
• Cisco Cisco Ise Passive Identity Connector: version 3.2.0 only; version 3.1.0 only; version 3.3.0 only; version 3.4.0 only; version 3.5.0 only

Published 2026-09-16. Last modified 2026-09-18.