CVE-2025-6091 is a critical buffer overflow vulnerability identified in the H3C GR-3000AX router, specifically in version V100R007L50. The flaw exists within the functions UpdateWanParamsMulti and UpdateIpv6Params located in the /routing/goform/aspForm component. The vulnerability arises due to improper handling and validation of the 'param' argument, which can be manipulated remotely to overflow a buffer. This overflow can lead to arbitrary code execution or denial of service conditions. The attack vector is network-based (AV:N), requiring no user interaction (UI:N) and no authentication (PR:L, meaning low privileges or possibly none). The vulnerability impacts confidentiality, integrity, and availability at a high level (VC:H, VI:H, VA:H), indicating that successful exploitation could allow an attacker to fully compromise the device. Although the vendor acknowledges the issue, they currently assess the risk as low and have no immediate plans for remediation. The CVSS 4.0 base score is 8.7, categorizing it as a high-severity vulnerability. No public exploits have been observed in the wild yet, but the exploit code has been disclosed publicly, increasing the risk of exploitation. Given the critical role of the GR-3000AX in routing and network infrastructure, exploitation could severely disrupt network operations and compromise sensitive data passing through the device.

For European organizations, the exploitation of this vulnerability could have significant consequences. The H3C GR-3000AX is a high-performance router often deployed in enterprise and service provider networks. A successful attack could lead to full device compromise, allowing attackers to intercept, modify, or disrupt network traffic, potentially affecting confidentiality and integrity of sensitive communications. Availability could also be impacted, causing network outages or degraded performance. This is particularly critical for sectors relying on uninterrupted network connectivity such as finance, telecommunications, healthcare, and government. The remote and unauthenticated nature of the exploit increases the risk of widespread attacks, especially in environments where patching is delayed or vendor support is limited. Additionally, the lack of immediate vendor remediation means organizations must proactively manage the risk. The public disclosure of exploit details further elevates the threat, as it lowers the barrier for attackers to develop and deploy attacks targeting this vulnerability.

Given the absence of an official patch, European organizations should implement the following specific mitigation strategies: 1) Network Segmentation: Isolate H3C GR-3000AX devices from untrusted networks and limit management access to trusted administrative networks only. 2) Access Control Lists (ACLs): Apply strict ACLs to restrict inbound traffic to only necessary sources and protocols, minimizing exposure of the vulnerable functions. 3) Intrusion Detection/Prevention Systems (IDS/IPS): Deploy and tune IDS/IPS signatures to detect and block attempts to exploit buffer overflow patterns targeting the UpdateWanParamsMulti and UpdateIpv6Params functions. 4) Firmware Upgrade Planning: Engage with H3C support to obtain timelines for patches or consider upgrading to unaffected firmware versions if available. 5) Monitoring and Logging: Enhance logging on affected devices and monitor for unusual activity or crashes indicative of exploitation attempts. 6) Incident Response Preparedness: Prepare for rapid containment and recovery in case of compromise, including device isolation and forensic analysis. 7) Vendor Communication: Maintain close communication with H3C for updates and advisories. 8) Alternative Hardware Evaluation: For critical environments, evaluate the feasibility of replacing vulnerable devices with alternatives that have active security support.