Westermo Network Technologies WeOS 5

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1. EXECUTIVE SUMMARY CVSS v4 8.2 ATTENTION: Exploitable remotely Vendor: Westermo Network Technologies Equipment: WeOS 5 Vulnerability: Improper Validation of Syntactic Correctness of Input
2. RISK EVALUATION Successful exploitation of this vulnerability could cause the device to reboot.
3. TECHNICAL DETAILS 3.1 AFFECTED PRODUCTS Westermo reports following versions of WeOS 5, an industrial network operating system, are affected: WeOS 5: Versions 5.23.0 and prior 3.2 VULNERABILITY OVERVIEW 3.2.1 IMPROPER VALIDATION OF SYNTACTIC CORRECTNESS OF INPUT CWE-1286 When configured for IPSec, a Westermo device running WeOS 5 could be vulnerable to a denial-of-service attack. A specifically crafted ESP packet could trigger an immediate reboot of the device. CVE-2025-46419 has been assigned to this vulnerability. A CVSS v3.1 base score of 5.9 has been calculated; the CVSS vector string is (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H). A CVSS v4 score has also been calculated for CVE-2025-46419. A base score of 8.2 has been calculated; the CVSS vector string is (CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N). 3.3 BACKGROUND CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities, Critical Manufacturing, Energy, Water and Wastewater Systems COUNTRIES/AREAS DEPLOYED: Worldwide COMPANY HEADQUARTERS LOCATION: Sweden 3.4 RESEARCHER Westermo Network Technologies reported this vulnerability to CISA.
4. MITIGATIONS Westermo recommends upgrading to the latest WeOS 5 version available. The vulnerability has been addressed and removed in WeOS 5 Version 5.24.0. This version is available for download on the Westermo Network Technologies support site. For more information refer to Westermo’s security advisory Westermo-25-02. CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability, such as: Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the Internet. Locate control system networks and remote devices behind firewalls and isolating them from business networks. When remote access is required, use more secure methods, such as virtual private networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices. CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures. CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies. Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents. No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability has a high attack complexity.
5. UPDATE HISTORY September 18, 2025: Initial Republication of Westermo’s security advisory Westermo-25-02