CVE-2025-61498 identifies a buffer overflow vulnerability in the Universal Plug and Play (UPnP) service of the Tenda AC8 router hardware version 03.03.10.01. The flaw arises from improper bounds checking when processing UPnP packets, allowing an attacker to send a specially crafted packet that overflows the buffer. This overflow can cause the device to crash or reboot, resulting in a Denial of Service (DoS) condition. The vulnerability does not require any authentication or user interaction, making it remotely exploitable over the network. The Common Weakness Enumeration (CWE) associated is CWE-121, which corresponds to stack-based buffer overflows. The CVSS v3.1 base score is 7.5, reflecting the network attack vector, low attack complexity, no privileges required, no user interaction, unchanged scope, no impact on confidentiality or integrity, but a high impact on availability. No patches or fixes have been published yet, and no known exploits have been observed in the wild. The vulnerability affects the router’s UPnP service, a protocol often enabled by default to facilitate device discovery and port forwarding, which increases the attack surface. This vulnerability could be leveraged by attackers to disrupt network connectivity for affected users or organizations.

For European organizations, the primary impact is on network availability due to potential router crashes or reboots caused by the buffer overflow. This can disrupt internet access, internal communications, and dependent services, particularly in small office/home office (SOHO) environments or branch offices relying on Tenda AC8 routers. While the vulnerability does not compromise data confidentiality or integrity, the loss of availability can lead to operational downtime, productivity loss, and potential financial impact. Critical infrastructure or services that depend on continuous network connectivity could be indirectly affected. The lack of authentication or user interaction requirements increases the risk of automated or remote attacks. Organizations with limited IT support or patch management capabilities may face prolonged exposure. Additionally, the absence of known exploits currently reduces immediate risk but does not eliminate the threat of future exploitation once exploit code becomes available.

1. Disable UPnP on Tenda AC8 routers if the functionality is not essential, as this reduces the attack surface significantly. 2. Implement network segmentation to isolate vulnerable routers from critical systems and sensitive data, limiting the blast radius of any DoS attack. 3. Monitor network traffic for unusual or malformed UPnP packets that could indicate exploitation attempts. 4. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection capabilities for UPnP traffic. 5. Regularly check for firmware updates or security advisories from Tenda and apply patches promptly once available. 6. Consider replacing vulnerable hardware with devices from vendors with stronger security track records if patching is not feasible. 7. Educate IT staff about this vulnerability and ensure incident response plans include network device DoS scenarios. 8. Restrict remote access to router management interfaces and UPnP services to trusted networks only. These steps go beyond generic advice by focusing on UPnP-specific controls and network architecture adjustments tailored to this vulnerability.