Cisco disclosed a critical authentication‑bypass vulnerability (CVE‑2026‑76460) affecting its Identity Services Engine, with active exploitation and a maximum CVSS score of 10.0.

Cisco has disclosed a critical authentication‑bypass flaw (CVE‑2026‑76460) in its Identity Services Engine (ISE) that carries a perfect CVSS 10.0 rating and is already being exploited in the wild.

Vulnerability details

The flaw resides in the ISE authentication flow, allowing an unauthenticated attacker to bypass credential checks and gain administrative access to the management interface. Cisco rates the vulnerability as "critical" and assigns it the maximum CVSS score of 10.0, reflecting its ease of exploitation and severe impact.

Active exploitation

Security researchers observed active exploitation shortly after the vulnerability was first reported. Attackers are leveraging the bug to obtain full control of affected ISE deployments, which are commonly used for network access control and policy enforcement in enterprise environments.

Cisco’s response

Cisco released an emergency patch alongside detailed remediation guidance. Administrators are urged to apply the update immediately, disable any unnecessary ISE services, and review logs for signs of unauthorized access.

  • Verify ISE version and apply the latest security update
  • Restrict management access to trusted IP ranges
  • Enable multi‑factor authentication for all admin accounts
  • Monitor authentication logs for anomalous activity

The rapid disclosure and patching underscore the importance of timely updates for security‑critical infrastructure components.

The Register coverage of Cisco’s perfect‑10 zero‑day