Cisco alerts customers to second actively exploited zero-day in as many days
Vulnerability: Cisco warns of a second critical zero-day (CVE-2026-76460) in ISE, enabling full device takeover, with active exploitation confirmed.
Deep Analysis and Expert Commentary
The vulnerability in Cisco ISE's API exposes a critical authentication bypass flaw, granting attackers root access. This compromise allows adversaries to manipulate network access policies, exfiltrate credentials, delete logs, and pivot across network segments. The lack of workarounds necessitates immediate patching. Given ISE's role in network access control, exploitation poses severe risks to organizational security postures. Historical targeting of ISE vulnerabilities (e.g., CVE-2025-20337, CVE-2025-20281) suggests sustained attacker interest. Defenders should prioritize patching, monitor for IoCs, and review ISE logs for anomalous activity. The consecutive disclosure of unrelated zero-days underscores the need for robust vulnerability management processes.
Action Items
- Immediately patch affected Cisco ISE systems to the latest fixed software version.
- Monitor network traffic and ISE logs for signs of exploitation using Cisco's provided IoCs.
- Review and restrict API access to ISE devices to minimize attack surface.
Original Article Brief Intro
CyberScoop · 2026-09-17 · Vulnerability: Cisco warns of a second critical zero-day (CVE-2026-76460) in ISE, enabling full device takeover, with active exploitation confirmed.
Related Terms and Notes
CVE IDs
- CVE-2026-76460 — Critical authentication bypass vulnerability in Cisco ISE allowing full device compromise.
- CVE-2026-76461
Techniques / TTPs
- Cisco ISE — Identity Services Engine, a network access policy enforcement platform.
- Zero-Day
Context Notes
- Authentication Bypass
- Cisco ISE