CVE-2025-20286 is a critical vulnerability affecting Cisco Identity Services Engine (ISE) software deployed specifically in cloud environments such as Amazon Web Services (AWS), Microsoft Azure, and Oracle Cloud Infrastructure (OCI). The root cause of this vulnerability is the use of hard-coded or improperly generated credentials during the deployment of Cisco ISE on these cloud platforms. This results in multiple Cisco ISE deployments sharing identical credentials if they are running the same software release on the same cloud platform. An unauthenticated remote attacker can exploit this flaw by extracting these shared credentials from one compromised Cisco ISE instance and then using them to access other Cisco ISE deployments across different cloud environments. Exploitation does not require user interaction or prior authentication and can be performed remotely over the network via unsecured ports. The attacker could gain access to sensitive data, perform limited administrative operations, modify system configurations, or disrupt services, potentially impacting the confidentiality, integrity, and availability of the affected systems. Notably, this vulnerability only affects deployments where the Primary Administration node is hosted in the cloud; on-premises Primary Administration nodes are not vulnerable. The affected versions span multiple releases from 3.1.0 through 3.4 Patch 1 and various patches in between. The CVSS v3.1 base score is 9.9, indicating a critical severity with network attack vector, low attack complexity, no privileges required, no user interaction, and scope change. Although no known exploits are currently reported in the wild, the vulnerability's nature and severity make it a significant threat to cloud-based Cisco ISE deployments.

For European organizations, this vulnerability poses a severe risk, especially for those leveraging Cisco ISE in cloud environments to manage network access and security policies. Cisco ISE is widely used in enterprises and government sectors for identity and access management, network segmentation, and policy enforcement. Exploitation could lead to unauthorized access to sensitive corporate or governmental data, manipulation of network access controls, and potential disruption of critical network services. Given the shared credentials across deployments, a single compromised instance could cascade into multiple affected environments, amplifying the impact. This could result in data breaches, regulatory non-compliance (e.g., GDPR violations), operational downtime, and reputational damage. The ability to perform administrative operations remotely without authentication further exacerbates the threat, enabling attackers to pivot within networks or disrupt services at scale. The impact is particularly critical for sectors with stringent security requirements such as finance, healthcare, telecommunications, and public administration within Europe.

European organizations should immediately assess their Cisco ISE deployments to determine if the Primary Administration node is cloud-hosted and if the affected versions are in use. Specific mitigation steps include: 1) Upgrading Cisco ISE to the latest patched versions where Cisco has addressed the credential generation issue; 2) Restricting network access to Cisco ISE management interfaces by implementing strict firewall rules and network segmentation to limit exposure to unsecured ports; 3) Employing multi-factor authentication (MFA) and strong access controls around Cisco ISE administrative interfaces; 4) Monitoring network traffic and logs for suspicious access patterns indicative of credential reuse or unauthorized administrative actions; 5) Considering migration of Primary Administration nodes to on-premises environments where feasible to avoid exposure; 6) Applying cloud provider security best practices such as private networking, VPNs, or dedicated connectivity to reduce attack surface; 7) Conducting regular security audits and penetration testing focused on Cisco ISE deployments; 8) Preparing incident response plans specifically addressing potential compromise scenarios related to this vulnerability. These targeted actions go beyond generic advice by focusing on deployment architecture, access controls, and proactive detection tailored to the nature of this vulnerability.