CVE-2025-5451 is a stack-based buffer overflow vulnerability identified in Ivanti Connect Secure and Ivanti Policy Secure products prior to versions 22.7R2.8 and 22.7R1.5 respectively. This vulnerability is classified under CWE-121, which pertains to improper handling of buffer boundaries leading to stack-based buffer overflows. The flaw allows a remote attacker who already has administrative privileges and is authenticated to the system to trigger a denial of service (DoS) condition. Specifically, the attacker can exploit the buffer overflow to crash the application or service, thereby disrupting availability. The vulnerability does not impact confidentiality or integrity directly, as it requires high privileges and authentication, and there is no indication of code execution or data leakage. The CVSS v3.1 base score is 4.9 (medium severity), with vector AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H, indicating network attack vector, low attack complexity, high privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, but high impact on availability. No known exploits are currently reported in the wild, and no patches or mitigations are linked in the provided data, though the vendor has released fixed versions. The vulnerability affects versions before 22.7R2.8 for Connect Secure and before 22.7R1.5 for Policy Secure, so organizations running older versions are at risk. This vulnerability is significant because Ivanti Connect Secure is widely used for secure remote access and VPN services, making availability disruptions potentially impactful to business continuity.

For European organizations, the primary impact of CVE-2025-5451 is the potential disruption of remote access services provided by Ivanti Connect Secure and Policy Secure appliances. Since these products are commonly deployed to enable secure VPN connections for remote employees and partners, a successful exploitation could result in denial of service, preventing legitimate users from accessing critical internal resources. This can lead to operational downtime, reduced productivity, and potential delays in business processes reliant on remote connectivity. Although the vulnerability does not allow data theft or system compromise beyond DoS, the loss of availability in a remote access solution can have cascading effects, especially for organizations with distributed workforces or critical infrastructure requiring continuous remote management. Additionally, the requirement for administrative privileges limits the attack surface to insiders or compromised admin accounts, but insider threats or credential theft scenarios cannot be discounted. In sectors such as finance, healthcare, and government within Europe, where secure remote access is essential and regulated, such disruptions could also have compliance and reputational consequences.

European organizations should prioritize upgrading Ivanti Connect Secure to version 22.7R2.8 or later, and Ivanti Policy Secure to version 22.7R1.5 or later, as these versions contain fixes for the buffer overflow vulnerability. Until patching is possible, organizations should implement strict access controls to limit administrative access only to trusted personnel and monitor admin account activities for suspicious behavior. Employing multi-factor authentication (MFA) for admin accounts can reduce the risk of credential compromise. Network segmentation should be used to isolate management interfaces of Ivanti appliances from general network access, limiting exposure to potential attackers. Additionally, organizations should enable and review detailed logging and alerting on the Ivanti devices to detect anomalous admin activities that could indicate exploitation attempts. Regular vulnerability scanning and penetration testing focusing on remote access infrastructure can help identify residual risks. Finally, incident response plans should include procedures for rapid recovery from DoS conditions affecting remote access services to minimize operational impact.