CVE-2026-20147
Published: 15 April 2026
Summary
CVE-2026-20147 is a critical-severity Command Injection (CWE-77) vulnerability in Cisco ISE (inferred from references). Its CVSS base score is 9.9 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation of Remote Services (T1210); ranked in the top 4.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-20147 is a high-severity vulnerability affecting Cisco Identity Services Engine (ISE) and Cisco ISE-PIC. It stems from insufficient validation of user-supplied input, classified under CWE-77 (Command Injection), with a CVSS v3.1 base score of 9.9 (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H). Published on April 15, 2026, the flaw enables an authenticated, remote attacker possessing valid administrative credentials to execute arbitrary commands on the underlying operating system of an affected device by sending a crafted HTTP request.
An attacker with administrative privileges can exploit this vulnerability over the network with low complexity and no user interaction required. Successful exploitation grants initial user-level access to the operating system, followed by privilege escalation to root. In single-node ISE deployments, it can additionally trigger a denial-of-service (DoS) condition, rendering the node unavailable and preventing unauthenticated endpoints from accessing the network until restoration.
The official Cisco Security Advisory provides details on mitigation strategies and available patches; refer to https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-rce-traversal-8bYndVrZ for remediation guidance.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-22962
Vulnerability details
A vulnerability in Cisco ISE and Cisco ISE-PIC could allow an authenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device. To exploit this vulnerability, the attacker must have valid administrative credentials. This vulnerability…
more
is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root. In single-node ISE deployments, successful exploitation of this vulnerability could cause the affected ISE node to become unavailable, resulting in a denial of service (DoS) condition. In that condition, endpoints that have not already authenticated would be unable to access the network until the node is restored.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Command injection (CWE-77) in Cisco ISE web interface enables authenticated remote arbitrary OS command execution (T1210: Exploitation of Remote Services; T1059.004: Unix Shell), with privilege escalation and DoS potential.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly addresses the root cause of command injection by requiring validation of user-supplied input in crafted HTTP requests to the Cisco ISE device.
Mandates timely identification, reporting, and remediation of flaws like this input validation vulnerability through patching as recommended in the Cisco advisory.
Enforces least privilege to limit administrative access and mitigate damage from privilege escalation to root following initial exploitation.