In plain language
What this advisory means
On September 16, 2026, Cisco announced multiple security vulnerabilities in its Identity Services Engine (ISE) software. These issues include critical flaws like authentication bypass, remote code execution, command injection, denial of service, and SQL injection. Cisco strongly recommends customers upgrade to the new fixed software versions to protect their systems.
Technical explanation
How the issue affects the environment
Cisco's Identity Services Engine contains numerous security vulnerabilities affecting its core functionality, including critical authentication bypasses (CVE-2026-76460), remote code execution (CVE-2026-20211, CVE-2026-20176, CVE-2026-20307), command injection (CVE-2026-20306, CVE-2026-20305), and RADIUS protocol denial of service (CVE-2026-20352). These flaws allow attackers to bypass security controls, execute arbitrary code on systems with elevated privileges, and disrupt authentication services, potentially compromising network security and availability. Exploiting these requires network access and in some cases valid credentials. Cisco has released hardening updates and fixed software versions addressing these security issues.
Operational impact
Why teams should care
Exploitation of these vulnerabilities could lead to unauthorized network access, disruption of authentication services, and control over security infrastructure. This risks organizational data confidentiality, integrity, and availability, potentially causing operational downtime, data breaches, and reputational damage. Immediate remediation by applying fixed software is essential to mitigate these risks.
Immediate action
Cisco strongly recommends upgrading to the fixed software releases indicated in the advisories published on September 16, 2026. Customers should contact Cisco Technical Assistance Center for support and ensure their systems meet upgrade requirements before applying patches.
Affected and fixed releases
Temporary risk reduction
No workarounds are available as per Cisco advisories. Immediate software upgrade is advised.
Evidence and validation checklist
- Cisco official advisory published September 16, 2026
- List of CVEs with critical severity assigned
- Cisco recommendation to upgrade to fixed software
- No workarounds available noted in advisory
Authoritative reference
Cisco PSIRT Advisories
QCS detected and normalized this record from the official source. Vendor guidance remains authoritative.