CVE-2025-28030 is a high-severity stack overflow vulnerability identified in the TOTOLINK A810R router firmware version V4.1.2cu.5182_B20201026. The vulnerability arises from improper handling of the startTime and endTime parameters within the setParentalRules function. Specifically, these parameters are susceptible to a stack-based buffer overflow (CWE-121), which occurs when input data exceeds the allocated buffer size on the stack, leading to memory corruption. Exploiting this vulnerability could allow an unauthenticated remote attacker to execute arbitrary code with high privileges on the affected device. The CVSS v3.1 base score of 8.8 reflects the critical nature of this flaw, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The impact metrics indicate high confidentiality, integrity, and availability impacts (C:H/I:H/A:H), meaning a successful exploit could lead to complete compromise of the device, including data theft, manipulation, or denial of service. Although no known exploits are currently reported in the wild, the vulnerability's characteristics make it a prime candidate for exploitation, especially given the widespread use of TOTOLINK routers in consumer and small business environments. The lack of an official patch at the time of disclosure increases the urgency for mitigation and monitoring. The vulnerability is particularly concerning because routers serve as critical network infrastructure, and compromise could facilitate lateral movement into internal networks or interception of sensitive communications.

For European organizations, the exploitation of CVE-2025-28030 could have significant consequences. TOTOLINK routers are commonly deployed in small to medium enterprises and residential environments across Europe, often serving as the primary gateway to the internet. A successful attack could lead to unauthorized access to internal networks, data exfiltration, disruption of business operations, and potential pivoting to other critical systems. The high impact on confidentiality, integrity, and availability means that sensitive corporate data could be exposed or altered, and network availability could be severely disrupted. This is especially critical for sectors with stringent data protection requirements such as finance, healthcare, and government agencies. Additionally, compromised routers could be leveraged as part of botnets or for launching further attacks, amplifying the threat landscape. The requirement for user interaction (UI:R) suggests that social engineering or phishing tactics might be used to trigger the exploit, increasing the risk in environments where users are not adequately trained or where security awareness is low.

Immediately audit all TOTOLINK A810R routers in the network to identify affected firmware versions (V4.1.2cu.5182_B20201026). Apply firmware updates as soon as an official patch is released by TOTOLINK. In the absence of a patch, consider temporary mitigations such as disabling the parental control feature or restricting access to the router's management interface to trusted IP addresses only. Implement network segmentation to isolate vulnerable routers from critical internal systems, reducing the potential impact of a compromise. Enforce strict access controls on router management interfaces, including changing default credentials, enabling multi-factor authentication if supported, and restricting remote management capabilities. Monitor network traffic for unusual patterns indicative of exploitation attempts, such as unexpected outbound connections or anomalous DNS queries. Educate users about the risks of interacting with unsolicited prompts or links that could trigger the vulnerability, given the requirement for user interaction. Deploy intrusion detection/prevention systems (IDS/IPS) with updated signatures to detect attempts to exploit this specific stack overflow. Maintain an inventory of all network devices and regularly verify firmware versions to ensure timely application of security updates.