Cyber Posture

CVE-2026-20186

Critical

Published: 15 April 2026

Published
15 April 2026
Modified
17 April 2026
KEV Added
Patch
CVSS Score 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.0028 51.8th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

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…

more

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.

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly mitigates the insufficient validation of user-supplied input that enables command injection via crafted HTTP requests.

prevent

Addresses the underlying flaw in Cisco ISE by requiring identification, reporting, and correction through patching or updates.

prevent

Enforces least privilege to restrict Read Only Admin accounts from executing arbitrary commands or escalating to root privileges.

Security SummaryAI

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.

Details

CWE(s)

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.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
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

References