CVE-2025-20264: Cisco ISE Auth Bypass Vulnerability

CVE-2025-20264 Overview

A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an authenticated, remote attacker to bypass the authorization mechanisms for specific administrative functions. This authorization bypass vulnerability is due to insufficient authorization enforcement mechanisms for users created by SAML SSO integration with an external identity provider.

An attacker could exploit this vulnerability by submitting a series of specific commands to an affected device. A successful exploit could allow the attacker to modify a limited number of system settings, including some that would result in a system restart. In single-node Cisco ISE deployments, devices that are not authenticated to the network will not be able to authenticate until the Cisco ISE system comes back online.

Critical Impact

Authenticated attackers can bypass authorization controls to modify system settings and potentially trigger service restarts, causing network authentication disruptions in single-node ISE deployments.

Affected Products

• Cisco Identity Services Engine 3.0.0 (including patches 1-8)
• Cisco Identity Services Engine 3.1.0 (including patches 1-10)
• Cisco Identity Services Engine 3.2.0 (including patches 1-7)
• Cisco Identity Services Engine 3.3.0 (including patches 1-4)
• Cisco Identity Services Engine 3.4.0 (including patch 1)

Discovery Timeline

• June 25, 2025 - CVE-2025-20264 published to NVD
• July 8, 2025 - Last updated in NVD database

Technical Details for CVE-2025-20264

Vulnerability Analysis

This vulnerability represents a CWE-285 (Improper Authorization) weakness in Cisco Identity Services Engine's web-based management interface. The authorization bypass specifically affects users that were provisioned through SAML Single Sign-On (SSO) integration with external identity providers.

The vulnerability allows authenticated users with lower privilege levels to access and execute administrative functions that should be restricted based on their assigned role. The flaw exists in how the ISE management interface validates authorization for SAML-provisioned user accounts when processing administrative API requests.

The scope of the vulnerability is changed (S:C in CVSS vector), meaning the vulnerability can affect resources beyond its security scope. While the attacker requires low privileges (authentication via SAML SSO), no user interaction is needed to exploit this flaw. The impact includes potential modification of system settings (integrity impact) and service availability issues through forced system restarts.

Root Cause

The root cause of CVE-2025-20264 lies in insufficient authorization enforcement mechanisms within the Cisco ISE web management interface. When users are created through SAML SSO integration with an external identity provider, the authorization checks applied to these accounts do not properly enforce the expected permission boundaries.

Specifically, the authorization logic fails to adequately validate whether SAML-provisioned users have the appropriate privileges before allowing them to execute certain administrative commands. This creates a gap between the intended access control policy and the actual enforcement, enabling privilege boundary violations.

Attack Vector

The attack vector for this vulnerability is network-based and requires the following conditions:

1. Authentication Required: The attacker must have valid credentials to authenticate to the Cisco ISE management interface through SAML SSO integration
2. SAML SSO Configuration: The target ISE deployment must have SAML SSO integration configured with an external identity provider
3. Command Submission: The attacker submits a series of specific crafted commands through the web-based management interface

The exploitation does not require any user interaction and can be performed remotely over the network. Upon successful exploitation, the attacker gains the ability to modify system settings that exceed their authorized permissions, potentially including configurations that trigger a system restart.

In single-node ISE deployments, a forced restart creates a denial of service condition where network devices cannot authenticate until ISE comes back online, making this particularly impactful for smaller deployments without redundancy.

Detection Methods for CVE-2025-20264

Indicators of Compromise

• Unusual administrative configuration changes performed by SAML-authenticated users with limited permissions
• Unexpected system restart events on Cisco ISE appliances without corresponding authorized maintenance windows
• Log entries showing SAML-provisioned users executing administrative commands outside their role scope
• Authentication failures from network endpoints following unexpected ISE service restarts

Detection Strategies

• Review Cisco ISE audit logs for administrative actions performed by SAML SSO-provisioned users, focusing on configuration modifications
• Monitor for anomalous patterns of administrative API requests originating from accounts with limited administrative privileges
• Implement alerting on unexpected ISE service restarts or configuration file modifications
• Correlate SAML authentication events with subsequent administrative actions to identify permission boundary violations

Monitoring Recommendations

• Enable comprehensive logging for the ISE management interface, including all administrative command executions
• Configure SIEM rules to detect authorization bypass attempts by correlating user role assignments with executed administrative functions
• Implement real-time monitoring of ISE system status and service availability to detect exploitation attempts targeting service disruption
• Establish baseline behavioral patterns for SAML-authenticated administrative users to identify anomalous activity

How to Mitigate CVE-2025-20264

Immediate Actions Required

• Review the Cisco Security Advisory for specific patch information and apply applicable security updates
• Audit all SAML SSO-provisioned user accounts for appropriate permission assignments and remove unnecessary privileges
• Consider temporarily disabling SAML SSO integration if patches cannot be immediately applied and alternative authentication methods are available
• Implement additional network segmentation to restrict access to the ISE management interface from untrusted network segments

Patch Information

Cisco has released security updates to address this vulnerability. Organizations should consult the Cisco Security Advisory for detailed patch information specific to their deployed ISE version. The advisory covers affected versions across the 3.0.x, 3.1.x, 3.2.x, 3.3.x, and 3.4.x release trains.

Administrators should prioritize patching single-node ISE deployments due to the increased impact of potential service disruptions on network authentication availability.

Workarounds

• Restrict access to the Cisco ISE management interface to trusted administrative networks only using firewall rules or access control lists
• Implement multi-node ISE deployments where possible to mitigate the availability impact of potential exploitation
• Review and harden SAML SSO configurations, ensuring the external identity provider properly assigns limited roles to non-administrative users
• Enable additional authentication factors for ISE management access beyond SAML SSO where supported

# Example: Restrict ISE management interface access at the network level
# Apply firewall rules to limit management access to trusted admin subnets

# Cisco ASA firewall rule example
access-list MGMT-ACL extended permit tcp 10.0.100.0 255.255.255.0 host 192.168.1.10 eq 443
access-list MGMT-ACL extended deny tcp any host 192.168.1.10 eq 443

# Review ISE SAML configuration and user role mappings
# Navigate to: Administration > Identity Management > External Identity Sources > SAML Id Providers
# Verify role attribute mapping restricts non-admin users appropriately