CVE-2025-6114 is a critical stack-based buffer overflow vulnerability identified in the D-Link DIR-619L router, specifically affecting firmware version 2.06B01. The vulnerability resides in the function form_portforwarding within the /goform/form_portforwarding endpoint. It is triggered by the manipulation of parameters such as ingress_name_%d, sched_name_%d, and name_%d, which are used to configure port forwarding rules. Improper handling of these input arguments leads to a stack-based buffer overflow, allowing an attacker to overwrite memory on the stack. This type of vulnerability can be exploited remotely without authentication or user interaction, as the vulnerable endpoint is accessible over the network. The overflow can potentially enable arbitrary code execution, leading to full compromise of the affected device. Although the product is no longer supported by the vendor, the exploit code has been publicly disclosed, increasing the risk of exploitation. The vulnerability has been assigned a CVSS 4.0 score of 8.7 (high severity), reflecting its network attack vector, low complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. No official patches or mitigations have been released due to the product’s end-of-life status, which complicates remediation efforts. This vulnerability is significant because routers like the DIR-619L often serve as critical network gateways, and compromise can lead to interception, manipulation, or disruption of network traffic, as well as pivoting into internal networks.

For European organizations, exploitation of CVE-2025-6114 could have severe consequences. Compromised routers can lead to unauthorized access to internal networks, data interception, and disruption of business operations. Given the router’s role as a network gateway, attackers could manipulate traffic, conduct man-in-the-middle attacks, or deploy malware within corporate environments. This is particularly concerning for small and medium enterprises (SMEs) and home offices that may still use legacy or unsupported D-Link DIR-619L devices due to budget constraints or lack of IT resources. Critical sectors such as finance, healthcare, and manufacturing could face data breaches, operational downtime, or regulatory non-compliance if such devices are exploited. The lack of vendor support and patches increases the risk, as organizations cannot rely on official firmware updates to remediate the issue. Additionally, the public availability of exploit code lowers the barrier for attackers, potentially increasing the frequency and scale of attacks targeting vulnerable devices in Europe.

Given the absence of official patches, European organizations should prioritize the following mitigations: 1) Immediate identification and inventory of all D-Link DIR-619L devices running firmware version 2.06B01 or earlier. 2) Replacement of affected devices with currently supported, secure router models from reputable vendors. 3) If replacement is not immediately feasible, isolate vulnerable routers on segmented network zones with strict firewall rules to limit exposure to untrusted networks, especially the internet. 4) Disable remote management features and restrict access to the /goform/form_portforwarding endpoint if possible, using access control lists or network segmentation. 5) Monitor network traffic for unusual patterns indicative of exploitation attempts, such as unexpected port forwarding rule changes or anomalous outbound connections. 6) Educate IT staff and users about the risks of using unsupported hardware and the importance of timely device upgrades. 7) Implement network-level intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect exploitation attempts targeting this vulnerability. These steps go beyond generic advice by focusing on compensating controls and network architecture adjustments to mitigate risk in the absence of vendor patches.