CVE-2025-60684 is a stack-based buffer overflow vulnerability identified in the ToToLink LR1200GB (version V9.1.0u.6619_B20230130) and NR1800X (version V9.1.0u.6681_B20230703) router firmware. The vulnerability resides in the cstecgi.cgi binary, specifically within the sub_42F32C function that processes the 'lang' parameter from HTTP requests to the router's web interface. The function uses the unsafe sprintf() function to construct Help URL strings into fixed-size stack buffers without validating the length of the input. This lack of bounds checking allows an attacker to supply a maliciously crafted 'lang' parameter that overflows the buffer, potentially overwriting adjacent stack memory. The consequences of this overflow include memory corruption and the possibility of arbitrary code execution on the device. Notably, exploitation does not require any authentication or user interaction, making it remotely exploitable by an unauthenticated attacker over the network. The vulnerability has been assigned a CVSS v3.1 base score of 6.5, reflecting medium severity, with the attack vector being network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), low confidentiality impact (C:L), no integrity impact (I:N), and low availability impact (A:L). There are no known public exploits or patches available at the time of publication. The underlying weakness corresponds to CWE-121: Stack-based Buffer Overflow. This vulnerability could be leveraged by attackers to disrupt router functionality or gain control over the device, potentially enabling further network compromise or denial of service.

For European organizations, the exploitation of CVE-2025-60684 could lead to partial denial of service or unauthorized code execution on affected ToToLink routers. This may disrupt network connectivity, degrade service availability, or allow attackers to pivot into internal networks. Confidentiality impact is limited but not negligible, as arbitrary code execution could enable attackers to intercept or manipulate network traffic. Organizations relying on these router models for critical infrastructure, small to medium enterprise networks, or branch office connectivity may face operational disruptions. The lack of authentication requirement increases the risk, especially if routers are exposed to the internet or poorly segmented networks. While no known exploits exist yet, the medium CVSS score and ease of exploitation warrant proactive mitigation to prevent potential attacks. The impact on integrity is minimal, but availability and confidentiality could be moderately affected depending on the attacker's goals and network environment.

1. Immediately restrict external access to the router's web management interface by implementing firewall rules or network segmentation to limit exposure to untrusted networks. 2. Monitor ToToLink's official channels for firmware updates addressing this vulnerability and apply patches promptly once available. 3. If firmware updates are not yet available, consider temporary mitigation by disabling or restricting access to the vulnerable cstecgi.cgi interface if possible. 4. Employ network intrusion detection/prevention systems (IDS/IPS) to detect anomalous HTTP requests targeting the 'lang' parameter or unusual buffer overflow patterns. 5. Conduct regular network scans to identify devices running the affected firmware versions and prioritize their remediation. 6. Educate network administrators about the vulnerability and encourage the use of strong administrative passwords and multi-factor authentication to reduce risk from other attack vectors. 7. Implement network segmentation to isolate critical systems from vulnerable routers to limit potential lateral movement in case of compromise.