CVE-2025-6112 is a critical buffer overflow vulnerability identified in the Tenda FH1205 router, specifically affecting firmware version 2.0.0.7. The vulnerability resides in the function fromadvsetlanip within the /goform/AdvSetLanip endpoint. An attacker can exploit this flaw by manipulating the 'lanMask' argument, which leads to a buffer overflow condition. This type of vulnerability can cause memory corruption, potentially allowing an attacker to execute arbitrary code remotely without requiring user interaction or prior authentication. The vulnerability is remotely exploitable over the network, as the affected function is accessible via a web interface endpoint. The CVSS 4.0 base score of 8.7 (high severity) reflects the ease of exploitation (network vector, low attack complexity, no privileges or user interaction required) and the significant impact on confidentiality, integrity, and availability (all rated high). Although no known exploits are currently observed in the wild, the public disclosure of the exploit code increases the risk of imminent attacks. The absence of official patches at the time of disclosure further elevates the threat level. Buffer overflow vulnerabilities in networking equipment like routers are particularly dangerous because they can lead to full device compromise, enabling attackers to intercept, modify, or disrupt network traffic, pivot into internal networks, or establish persistent footholds. Given the critical nature of this flaw and the widespread deployment of Tenda FH1205 in small office and home office environments, this vulnerability poses a significant security risk.

For European organizations, the exploitation of CVE-2025-6112 could result in severe consequences. Compromised routers can serve as entry points for attackers to infiltrate corporate or residential networks, leading to data breaches, espionage, or disruption of business operations. The integrity and confidentiality of sensitive information transmitted through these routers could be compromised. Additionally, attackers could leverage compromised devices to launch further attacks such as man-in-the-middle, DNS hijacking, or use the devices as part of botnets for distributed denial-of-service (DDoS) attacks. Small and medium enterprises (SMEs) and remote workers relying on Tenda FH1205 routers are particularly vulnerable, as these devices often lack robust security controls and monitoring. The potential for widespread exploitation is heightened by the public availability of exploit code and the lack of patches, increasing the risk of automated attacks targeting vulnerable devices across Europe. Disruption of network availability could also impact critical services, especially in sectors relying on stable internet connectivity. Overall, the threat undermines network security at the edge, potentially affecting confidentiality, integrity, and availability of organizational IT assets.

1. Immediate Network Segmentation: Isolate Tenda FH1205 devices from critical network segments to limit potential lateral movement if compromised. 2. Disable Remote Management: If remote web management is enabled on these routers, disable it to reduce the attack surface. 3. Monitor Network Traffic: Implement network monitoring to detect anomalous traffic patterns indicative of exploitation attempts, such as unusual requests to /goform/AdvSetLanip. 4. Firmware Upgrade or Replacement: Since no patches are currently available, consider replacing affected devices with routers from vendors providing timely security updates. 5. Access Control: Restrict access to router management interfaces to trusted IP addresses only, using firewall rules or VPNs. 6. Incident Response Preparedness: Prepare to respond to potential compromises by backing up configurations, maintaining logs, and having procedures to reset or replace devices quickly. 7. Vendor Engagement: Engage with Tenda for updates on patch availability and apply firmware updates immediately upon release. 8. User Awareness: Educate users about the risks of using vulnerable routers and encourage reporting of unusual device behavior. These steps go beyond generic advice by focusing on immediate containment, proactive monitoring, and strategic device management tailored to the specific vulnerability and device context.