CVE-2025-20283: Cisco Identity Services Engine RCE Flaw

CVE-2025-20283 Overview

CVE-2025-20283 is an authenticated remote code execution vulnerability in a specific API of Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC). The flaw stems from insufficient validation of user-supplied input. An attacker holding valid high-privileged credentials can submit a crafted API request and execute arbitrary commands on the underlying operating system as root. Cisco ISE is widely deployed for network access control and policy enforcement, making compromise of the appliance a direct path to broader network access. The vulnerability is tracked under [CWE-74] (Improper Neutralization of Special Elements in Output Used by a Downstream Component).

Critical Impact

Successful exploitation grants root-level command execution on ISE appliances, allowing complete takeover of the identity and access policy enforcement layer.

Affected Products

• Cisco Identity Services Engine 3.3.0 (base and patches 1–6)
• Cisco Identity Services Engine 3.4.0 (base and patch 1)
• Cisco Identity Services Engine Passive Identity Connector 3.3.0 and 3.4.0 (corresponding patch levels)

Discovery Timeline

• 2025-07-16 - CVE-2025-20283 published to the National Vulnerability Database
• 2025-07-22 - Last updated in NVD database

Technical Details for CVE-2025-20283

Vulnerability Analysis

The vulnerability resides in a specific API endpoint exposed by Cisco ISE and ISE-PIC. The endpoint accepts attacker-controlled input that is passed to a downstream operating system component without adequate neutralization. Because the ISE management processes run with elevated privileges, injected commands execute as root on the underlying Linux-based appliance.

Exploitation requires authentication with high-privileged credentials, which limits opportunistic mass-exploitation. However, ISE administrative accounts are high-value targets for credential theft, phishing, and insider abuse. A compromised administrator account, a stale service credential, or an attacker who has pivoted from another system can leverage this flaw to gain a persistent root foothold on the ISE node.

Once root code execution is achieved on an ISE appliance, the attacker can manipulate authentication policies, exfiltrate RADIUS and TACACS+ secrets, modify network access decisions, and pivot deeper into the enterprise.

Root Cause

The root cause is insufficient input validation in the affected API handler. User-supplied parameters are incorporated into a downstream command or interpreter context without sanitization, satisfying the [CWE-74] injection pattern. Cisco has not publicly disclosed the specific API path or parameter.

Attack Vector

The attack is delivered over the network against the ISE management API. The attacker authenticates with valid high-privileged credentials, then issues a crafted API request containing injected payload content. The ISE process passes the malicious input to the OS layer, where it is interpreted and executed as root. No user interaction is required.

No public proof-of-concept exploit is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS probability is approximately 0.7%.

Detection Methods for CVE-2025-20283

Indicators of Compromise

• Unexpected API requests to Cisco ISE administrative endpoints originating from non-administrative source addresses or outside maintenance windows.
• New or unexpected processes spawned by ISE service accounts, particularly shell interpreters or network utilities running as root.
• Unusual outbound network connections from ISE appliances to unknown external hosts.
• Modifications to ISE configuration files, scheduled tasks, or policy databases that do not correlate with authorized change tickets.

Detection Strategies

• Enable verbose API and administrative audit logging on Cisco ISE and forward logs to a centralized SIEM for correlation.
• Hunt for anomalous command execution patterns on the ISE underlying OS using host telemetry where available.
• Correlate administrative authentication events with subsequent API activity to identify credential abuse.
• Baseline normal ISE administrator behavior and alert on deviations such as off-hours API usage or new client IPs.

Monitoring Recommendations

• Monitor all high-privilege ISE account logins, including failed and successful attempts, and alert on logins from unexpected geographies or hosts.
• Track configuration changes and policy modifications inside ISE through change auditing.
• Continuously assess patch level of ISE nodes and alert when unpatched versions remain in production.

How to Mitigate CVE-2025-20283

Immediate Actions Required

• Apply the fixed software releases referenced in the Cisco Security Advisory to all ISE and ISE-PIC nodes running 3.3.x or 3.4.x.
• Audit all accounts with high-privileged ISE roles and remove unused or stale administrator credentials.
• Rotate credentials for any ISE administrator account that may have been exposed or shared.
• Restrict ISE management API exposure to dedicated administrative networks and jump hosts only.

Patch Information

Cisco has published fixed versions in the Cisco Security Advisory cisco-sa-ise-multi-3VpsXOxO. Customers running Cisco ISE 3.3 or 3.4 should upgrade to the fixed release identified in the advisory. Earlier major versions referenced in the advisory should be reviewed for applicability.

Workarounds

• No vendor workaround is documented; upgrading to the fixed release is the supported remediation path.
• As compensating controls, enforce network segmentation around ISE management interfaces and require multi-factor authentication for all administrative access.
• Limit which source networks can reach the ISE API using firewall ACLs or out-of-band management VLANs.