CVE-2025-48021 Overview
A vulnerability has been discovered in the Vnet/IP Interface Package provided by Yokogawa Electric Corporation. When affected products receive maliciously crafted packets, the Vnet/IP software stack process may be terminated, resulting in a denial of service condition. This integer underflow vulnerability (CWE-191) affects industrial control systems used in critical infrastructure environments.
Critical Impact
Exploitation of this vulnerability could terminate the Vnet/IP software stack process, potentially disrupting industrial control system operations in critical infrastructure environments.
Affected Products
- Vnet/IP Interface Package for CENTUM VP R6 (VP6C3300) - Version R1.07.00 or earlier
- Vnet/IP Interface Package for CENTUM VP R7 (VP7C3300) - Version R1.07.00 or earlier
Discovery Timeline
- 2026-02-13 - CVE-2025-48021 published to NVD
- 2026-02-13 - Last updated in NVD database
Technical Details for CVE-2025-48021
Vulnerability Analysis
This vulnerability is classified as an Integer Underflow (CWE-191), where arithmetic operations on integer values result in a value that wraps below the minimum representable value. In the context of the Vnet/IP Interface Package, this flaw exists in the network packet processing functionality. When the software stack receives specially crafted network packets, the integer underflow condition can be triggered, causing the Vnet/IP process to terminate unexpectedly.
The attack requires adjacent network access, meaning an attacker must be positioned on the same network segment as the target device. While no authentication is required to exploit this vulnerability, the attack complexity is considered high. Successful exploitation results in high availability impact as the affected service terminates, though no confidentiality or integrity impacts have been identified.
Root Cause
The root cause of this vulnerability is an integer underflow condition (CWE-191) within the Vnet/IP software stack's packet processing routines. When certain arithmetic operations are performed on packet data without proper boundary validation, the resulting value can underflow, leading to unexpected behavior that causes the process to terminate.
Attack Vector
The attack vector requires adjacent network access (not remotely exploitable over the internet). An attacker positioned on the same network segment as the vulnerable Yokogawa CENTUM VP system could send maliciously crafted network packets to the Vnet/IP interface. The crafted packets exploit the integer underflow condition in the packet processing logic, causing the Vnet/IP software stack to terminate. This denial of service could impact the availability of the distributed control system.
The attack does not require any privileges or user interaction, making it a concern for industrial environments where network segmentation may not be strictly enforced. For detailed technical information, refer to the Yokogawa Security Assessment Report.
Detection Methods for CVE-2025-48021
Indicators of Compromise
- Unexpected termination or crashes of the Vnet/IP software stack process on CENTUM VP systems
- Repeated service restarts on Vnet/IP Interface Package components
- Anomalous network traffic patterns targeting Vnet/IP communication ports from adjacent network segments
Detection Strategies
- Monitor for abnormal process terminations on CENTUM VP R6 and R7 systems running Vnet/IP Interface Package
- Implement network intrusion detection rules to identify malformed packets targeting Vnet/IP protocol communications
- Deploy industrial protocol-aware monitoring solutions to detect anomalous packet structures
- Review system logs for recurring Vnet/IP service failures or automatic restart events
Monitoring Recommendations
- Enable detailed logging on Vnet/IP Interface Package components and centralize log collection
- Configure alerting for any unexpected Vnet/IP process terminations in the SCADA/DCS monitoring system
- Monitor network traffic on segments containing CENTUM VP systems for unusual packet patterns
- Implement baseline monitoring for normal Vnet/IP communication patterns to detect deviations
How to Mitigate CVE-2025-48021
Immediate Actions Required
- Review and apply network segmentation to isolate CENTUM VP systems from untrusted network segments
- Restrict network access to Vnet/IP interfaces to only authorized systems and personnel
- Monitor for any available patches or firmware updates from Yokogawa Electric Corporation
- Implement firewall rules to control traffic to and from Vnet/IP Interface Package components
Patch Information
Organizations should consult the Yokogawa Security Assessment Report for official remediation guidance and patch availability. Contact Yokogawa Electric Corporation support for specific patch information applicable to your CENTUM VP deployment.
Workarounds
- Implement strict network segmentation to prevent unauthorized adjacent network access to CENTUM VP systems
- Deploy industrial firewalls or access control lists to limit network access to Vnet/IP interfaces
- Use VLANs and network access control (NAC) to restrict which devices can communicate with control system components
- Consider implementing application-level monitoring to detect and alert on abnormal Vnet/IP behavior
# Example network segmentation configuration (generic firewall concept)
# Restrict access to Vnet/IP interfaces from unauthorized segments
# Consult your specific firewall/network equipment documentation
# Allow only authorized SCADA workstations to access CENTUM VP Vnet/IP
# Deny all other adjacent network traffic to control system segments
# Implement logging for any denied connection attempts
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
