CVE-2025-46419 is a vulnerability identified in Westermo's WeOS operating system, specifically versions 5 through 5.23.0. The vulnerability arises from improper validation of the syntactic correctness of input, classified under CWE-1286. In this case, the affected input is a malformed Encapsulating Security Payload (ESP) packet. ESP is a protocol used to provide confidentiality, integrity, and authentication in IPsec communications. The vulnerability allows an attacker to send a specially crafted malformed ESP packet to a device running WeOS, which triggers an unintended reboot of the system. This reboot can cause temporary denial of service (DoS) by interrupting network operations managed by the device. Since WeOS is an operating system used primarily in industrial and critical infrastructure networking equipment such as routers and switches, this vulnerability could disrupt network availability and stability. Notably, there are no known exploits in the wild at the time of publication, and no patches have been released yet. The vulnerability does not require authentication but does require the attacker to send malicious ESP packets, which implies network-level access or the ability to inject packets into the network path. The improper validation of input syntax means the system does not correctly parse or verify the structure of ESP packets before processing, leading to a crash or reboot. This vulnerability highlights a weakness in the input validation mechanisms of WeOS's network stack, which could be exploited to cause service interruptions.

For European organizations, especially those operating critical infrastructure, industrial control systems, or telecommunications networks, this vulnerability poses a risk of network outages and service disruptions. Westermo devices running WeOS are often deployed in industrial automation, transportation, energy, and utility sectors, where network reliability is paramount. An attacker exploiting this vulnerability could cause repeated reboots of network devices, leading to intermittent or prolonged loss of connectivity, impacting operational continuity and safety systems. The confidentiality and integrity of data are not directly compromised by this vulnerability; however, availability is significantly affected. Disruptions in network availability could cascade into broader operational failures, especially in sectors reliant on real-time data and control. The lack of known exploits currently reduces immediate risk, but the potential for future exploitation remains. European organizations with remote or exposed network segments where ESP traffic is permitted are particularly vulnerable. Additionally, the absence of patches means organizations must rely on mitigation strategies until a fix is available.

1. Implement network segmentation and strict firewall rules to restrict ESP traffic only to trusted sources and necessary network segments, minimizing exposure to malformed packets. 2. Monitor network traffic for unusual or malformed ESP packets using intrusion detection/prevention systems (IDS/IPS) capable of deep packet inspection. 3. Employ rate limiting or filtering on ESP packets at network boundaries to reduce the risk of packet injection attacks. 4. Where possible, disable or restrict IPsec ESP processing on devices that do not require it, reducing the attack surface. 5. Maintain close communication with Westermo for timely updates and patches; plan for rapid deployment once a patch is released. 6. Conduct regular backups and implement high-availability configurations to minimize downtime in case of device reboot. 7. Perform vulnerability scanning and penetration testing focused on network protocols to identify similar weaknesses. 8. Educate network administrators about the vulnerability and signs of exploitation to enable rapid detection and response.