CVE-2026-20309

A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to conduct a reflected cross-site scripting (XSS) attack against a user of the interface. This vulnerability exists because the web-based management interface does not properly validate user-supplied input. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.

  • Published Sep 16, 2026
  • CVSS 6.1 medium
  • 0.2% chance of exploitation in the next 30 days (EPSS)

Affected software

CVE-2026-20309 at the National Vulnerability Database