CVE-2026-20186

CriticalRCEUpdated

Published: 15 April 2026

Published

15 April 2026

Modified

29 June 2026

KEV Added

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Patch

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CVSS Score v3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS Score 0.0591 92.3th percentile

Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-20186 is a critical-severity Command Injection (CWE-77) vulnerability in Cisco Identity Services Engine. 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 7.7% 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-2026-20186 is a command injection vulnerability (CWE-77) in Cisco Identity Services Engine (ISE) that enables an authenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device. The flaw arises from insufficient validation of user-supplied input, earning 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).

An attacker with at least Read Only Admin credentials can exploit the vulnerability by sending a crafted HTTP request to an affected ISE device. Successful exploitation provides user-level access to the operating system, allowing subsequent privilege escalation to root privileges. In single-node ISE deployments, exploitation can also trigger a denial-of-service condition, making the node unavailable and preventing unauthenticated endpoints from accessing the network until restoration.

The official Cisco Security Advisory at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-rce-4fverepv provides further details on affected versions, exploitation conditions, and recommended mitigations or patches.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-22973

Vulnerability details

A vulnerability in Cisco Identity Services Engine (ISE) 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 at least Read Only Admin…

credentials. This vulnerability 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 these vulnerabilities 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): CWE-77

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1210 Exploitation of Remote Services Lateral Movement

Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.

attack.mitre.org →

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

Why these techniques?

Command injection vulnerability enables remote exploitation of ISE service (T1210), arbitrary OS command execution via Unix shell (T1059.004), and user-level access facilitating privilege escalation to root (T1068).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0