CVE-2026-76439: Cisco Identity Services Engine

Medium severity, CVSS 5.3. EPSS: 0.3% chance of exploitation in the next 30 days.

A vulnerability in the endpoint posture status reporting functionality of the guest portal web application of Cisco ISE could allow an unauthenticated, remote attacker to submit forged posture status events into the endpoint posture pipeline. This vulnerability is due to insufficient authentication on an internal interface that is exposed through the guest portal. An attacker could exploit this vulnerability by sending a crafted request to an affected system. A successful exploit could allow the attacker to manipulate the posture status on the affected system.

Affected products

• Cisco Identity Services Engine: before 3.3.0 (fixed in 3.3.0); version 3.3.0 only; version 3.4.0 only; version 3.5.0 only
• Cisco Identity Services Engine Passive Identity Connector: before 3.3.0 (fixed in 3.3.0); version 3.3.0 only; version 3.4.0 only

Published 2026-09-16. Last modified 2026-09-28.