CVE-2025-4997 is a high-severity denial of service (DoS) vulnerability affecting the H3C R2+ProG product up to version 200R004. The vulnerability resides in the HTTP POST request handler component, specifically within multiple functions responsible for updating WAN parameters and managing MAC address lists and SSID configurations (e.g., UpdateWanParams, AddMacList, EditMacList, AddWlanMacList, EditWlanMacList, Edit_BasicSSID, Edit_GuestSSIDFor2P4G, Edit_BasicSSID_5G, SetAPInfoById). The root cause is the improper handling and manipulation of the 'param' argument in these functions, which can be exploited remotely without authentication or user interaction. An attacker can send crafted HTTP POST requests to the affected endpoints to trigger the vulnerability, causing the device to become unresponsive or crash, resulting in denial of service. Although the vendor was notified early, no response or patch has been issued, and public exploit details have been disclosed, increasing the risk of exploitation. The CVSS 4.0 base score of 7.1 reflects the vulnerability's ease of remote exploitation (network vector, low attack complexity, no privileges or user interaction required) and its significant impact on availability. The vulnerability affects network infrastructure devices that are critical for connectivity and network management, making it a serious concern for organizations relying on H3C R2+ProG devices.

For European organizations, the impact of this vulnerability can be substantial. H3C R2+ProG devices are typically used in enterprise and service provider environments for network routing and wireless access management. A successful exploitation can cause network outages by rendering these devices inoperative, disrupting business operations, communications, and access to critical services. This can lead to operational downtime, loss of productivity, and potential cascading effects on dependent systems. Additionally, denial of service attacks can be leveraged as part of larger multi-vector attacks or to distract security teams while other malicious activities occur. The lack of vendor response and absence of patches increases the window of exposure, forcing organizations to rely on mitigation or device replacement. Given that the attack requires no authentication or user interaction, any exposed device with accessible management interfaces is at risk, including those in remote or less monitored locations. This vulnerability could also affect managed service providers and telecom operators in Europe who use H3C devices, potentially impacting their customers and critical infrastructure.

1. Immediate network segmentation and access control: Restrict access to the management interfaces of H3C R2+ProG devices to trusted internal networks and specific management stations only, using firewall rules and VLAN segmentation. 2. Disable or restrict HTTP POST management interfaces if possible, or replace with more secure management protocols (e.g., SSH, HTTPS with strong authentication). 3. Monitor network traffic for unusual POST requests targeting the vulnerable endpoints and implement intrusion detection/prevention rules to block suspicious payloads manipulating the 'param' argument. 4. Implement rate limiting on management interfaces to reduce the risk of DoS attacks. 5. Maintain an inventory of all H3C R2+ProG devices and assess exposure, prioritizing those with public or wide network access for immediate mitigation or replacement. 6. Engage with H3C or authorized partners for updates or workarounds, and plan for device firmware upgrades once patches become available. 7. Prepare incident response plans specifically addressing potential DoS scenarios affecting network infrastructure devices. 8. Consider deploying redundant network paths and failover mechanisms to minimize operational impact in case of device failure.