CVE-2025-28032 is a high-severity pre-authentication buffer overflow vulnerability affecting multiple TOTOLINK router models, specifically the A800R V4.1.2cu.5137_B20200730, A810R V4.1.2cu.5182_B20201026, A830R V4.1.2cu.5182_B20201102, A950RG V4.1.2cu.5161_B20200903, A3000RU V5.9c.5185_B20201128, and A3100R V4.1.2cu.5247_B20211129. The vulnerability resides in the setNoticeCfg function, which processes the IpForm parameter. Due to improper bounds checking, an attacker can send a specially crafted request to this function without any authentication, triggering a buffer overflow. This overflow can lead to arbitrary code execution, denial of service, or system instability. The vulnerability is classified under CWE-121 (Stack-based Buffer Overflow), indicating that the overflow occurs on the stack, which can be exploited to overwrite return addresses or function pointers. The CVSS 3.1 base score is 7.3, reflecting a network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and impacts on confidentiality, integrity, and availability (C:L/I:L/A:L). No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability affects firmware versions released between mid-2020 and late 2021, suggesting that many deployed devices may still be vulnerable if not updated or replaced. Given the nature of the vulnerability, exploitation could allow remote attackers to gain control over affected routers, potentially enabling network traffic interception, manipulation, or disruption.

For European organizations, exploitation of this vulnerability could have significant consequences. TOTOLINK routers are commonly used in small to medium-sized enterprises and residential environments, often serving as the primary gateway to the internet. Successful exploitation could compromise network perimeter security, allowing attackers to intercept sensitive data, redirect traffic, or launch further attacks within the internal network. This could lead to breaches of personal data protected under GDPR, operational disruptions, and reputational damage. Additionally, compromised routers could be leveraged as part of botnets or for launching attacks against other targets, amplifying the threat landscape. Critical infrastructure or organizations relying on these devices for remote connectivity may face increased risk of service outages or espionage. The pre-authentication nature of the vulnerability means attackers do not need valid credentials, increasing the likelihood of exploitation if devices are exposed to the internet without adequate network segmentation or firewall protections.

1. Immediate network-level mitigation: Block external access to router management interfaces (e.g., HTTP/HTTPS ports) from untrusted networks to reduce exposure. 2. Device inventory and firmware verification: Identify all TOTOLINK devices in use, confirm firmware versions, and prioritize those matching the vulnerable versions. 3. Firmware updates: Monitor TOTOLINK official channels for security advisories and apply firmware updates as soon as patches become available. 4. Network segmentation: Isolate vulnerable devices in separate VLANs or subnets to limit lateral movement in case of compromise. 5. Intrusion detection: Deploy network monitoring tools to detect anomalous traffic patterns or exploitation attempts targeting the setNoticeCfg function or unusual requests to the IpForm parameter. 6. Access control: Disable remote management features if not required, or restrict management access to trusted IP addresses only. 7. Incident response readiness: Prepare for potential exploitation by establishing logs collection, backup configurations, and response plans specific to router compromise scenarios. 8. Vendor engagement: Engage with TOTOLINK or authorized distributors for support and to expedite patch availability. These steps go beyond generic advice by focusing on network-level controls, device-specific inventory management, and proactive monitoring tailored to the vulnerability's characteristics.