CVE-2025-2521 is a high-severity vulnerability affecting Honeywell's Experion PKS and OneWireless WDM systems, specifically involving a memory buffer overread in the Control Data Access (CDA) component. The root cause is improper restriction of operations within the bounds of a memory buffer (CWE-119), leading to improper index validation against buffer borders. This flaw allows an attacker to perform a buffer overread, which can be leveraged to execute arbitrary code remotely without requiring authentication or user interaction. The affected Honeywell products include multiple Experion PKS components such as C300 PCNT02, C300 PCNT05, FIM4, FIM8, UOC, CN100, HCA, C300PM, and C200E, across versions 520.1 through 520.2 TCU9 and 530 through 530 TCU3. Similarly, OneWireless WDM versions 322.1 through 322.4 and 330.1 through 330.3 are vulnerable. The vulnerability has a CVSS v3.1 base score of 8.6, indicating a high impact with network attack vector, low attack complexity, no privileges required, and no user interaction needed. Exploitation could lead to confidentiality and integrity loss, as well as significant availability disruption due to remote code execution capabilities. Honeywell recommends updating to the latest patched versions: Experion PKS 520.2 TCU9 HF1, 530.1 TCU3 HF1, and OneWireless 322.5 and 331.1. No known exploits are currently in the wild, but the potential impact on critical industrial control systems is substantial given the nature of the affected products, which are widely used in industrial automation and process control environments.

The vulnerability poses a significant risk to European organizations that rely on Honeywell Experion PKS and OneWireless WDM systems for industrial process control and automation. Successful exploitation could allow attackers to execute arbitrary code remotely, potentially leading to disruption or manipulation of critical infrastructure operations. This could result in operational downtime, safety hazards, data breaches, and loss of control over industrial processes. Confidentiality could be compromised through unauthorized data access, while integrity could be undermined by malicious alteration of control commands or system configurations. Availability is also at risk, as attackers could cause system crashes or denial of service. Given the critical role these systems play in sectors such as energy, manufacturing, and utilities, the impact on European organizations could be severe, affecting not only business continuity but also public safety and regulatory compliance.

European organizations should prioritize immediate patching by upgrading to the latest Honeywell software versions as recommended: Experion PKS 520.2 TCU9 HF1, 530.1 TCU3 HF1, and OneWireless 322.5 and 331.1. In addition to patching, organizations should implement network segmentation to isolate industrial control systems from general IT networks and restrict access to trusted personnel only. Deploying intrusion detection and prevention systems tailored for industrial protocols can help detect anomalous activities indicative of exploitation attempts. Regularly auditing and monitoring system logs for unusual behavior is critical. Organizations should also enforce strict access controls and multi-factor authentication for remote access to these systems. Conducting thorough vulnerability assessments and penetration testing focused on industrial control environments will help identify residual risks. Finally, establishing incident response plans specific to industrial control system breaches will improve preparedness and minimize impact in case of exploitation.