CVE-2025-5466 is a security vulnerability classified under CWE-776, which involves improper restriction of recursive entity references in Document Type Definitions (DTDs), commonly known as XML Entity Expansion or XML External Entity (XEE) attacks. This vulnerability affects multiple Ivanti products including Ivanti Connect Secure (versions before 22.7R2.8 or 22.8R2), Ivanti Policy Secure (before 22.7R1.5), Ivanti ZTA Gateway (before 22.8R2.3-723), and Ivanti Neurons for Secure Access (before 22.8R1.4). The flaw allows a remote attacker who has authenticated with administrative privileges to trigger a denial of service (DoS) condition by exploiting the XML parser’s handling of recursive entity references within DTDs. Specifically, the attacker can craft malicious XML payloads that cause excessive resource consumption (CPU and memory), leading to service disruption or crash of the affected systems. The vulnerability does not impact confidentiality or integrity directly but severely affects availability. The CVSS v3.1 base score is 4.9 (medium severity), reflecting that the attack vector is network-based, requires low attack complexity, but demands high privileges (admin authentication) and does not require user interaction. The issue was publicly disclosed on August 12, 2025, with fixes deployed on August 2, 2025. No known exploits are currently reported in the wild. This vulnerability highlights the risks associated with XML processing in enterprise security appliances, especially those exposed to administrative interfaces over the network.

For European organizations, the impact of CVE-2025-5466 can be significant, particularly for enterprises relying on Ivanti’s secure access and policy enforcement solutions. These products are often deployed in critical network security infrastructure, including VPN gateways, zero trust access controls, and policy management systems. A successful DoS attack could disrupt secure remote access capabilities, leading to downtime, loss of productivity, and potential exposure to other security risks due to interrupted security controls. Given that the vulnerability requires administrative authentication, the risk is primarily from insider threats or compromised admin credentials. However, the widespread use of Ivanti products in sectors such as finance, healthcare, government, and large enterprises across Europe means that service outages could have cascading effects on business continuity and regulatory compliance, especially under GDPR and other data protection laws. The denial of service could also impair incident response and security monitoring capabilities, increasing the risk of further exploitation during downtime.

To mitigate this vulnerability effectively, European organizations should: 1) Immediately apply the vendor-provided patches released on August 2, 2025, for all affected Ivanti products to eliminate the XML entity expansion flaw. 2) Restrict administrative access to Ivanti management interfaces using network segmentation, VPNs, and strict access control lists to limit exposure to trusted personnel only. 3) Implement multi-factor authentication (MFA) for all administrative accounts to reduce the risk of credential compromise. 4) Monitor logs and network traffic for unusual XML payloads or spikes in resource usage indicative of attempted XML entity expansion attacks. 5) Conduct regular security audits and penetration testing focused on XML processing components and administrative interfaces. 6) Consider deploying Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with signatures or heuristics to detect and block malicious XML payloads targeting this vulnerability. 7) Educate administrators on the risks of XML-based attacks and enforce strong password policies to minimize insider threat risks.