CVE-2018-25316 in W308R v2
Summary
by MITRE • 04/30/2026
Tenda W308R v2 V5.07.48 contains a cookie session weakness vulnerability that allows unauthenticated attackers to modify DNS settings by exploiting insufficient session validation. Attackers can send GET requests to the goform/AdvSetDns endpoint with a crafted admin language cookie to change DNS servers and redirect user traffic to malicious sites.
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Analysis
by VulDB Data Team • 08/20/2026
The Tenda W308R v2 running firmware version V5.07.48 exhibits a critical authentication bypass vulnerability rooted in insufficient session validation mechanisms within its web management interface. This flaw allows unauthenticated remote attackers to manipulate sensitive network configuration parameters, specifically the Domain Name System (DNS) settings, without possessing valid administrative credentials. The core technical deficiency lies in how the device handles HTTP requests directed at specific form endpoints; rather than strictly enforcing a verified active admin session for privileged operations, the system accepts and processes commands based on loosely validated or predictable cookie values. This architectural weakness effectively neutralizes the intended access control measures, granting external actors the ability to execute administrative functions as if they were legitimate users with full privileges.
From an operational perspective, this vulnerability enables attackers to redirect user traffic by altering the DNS server addresses assigned to connected clients. By sending crafted GET requests to the goform/AdvSetDns endpoint and injecting a manipulated admin language cookie, adversaries can force devices on the local network to resolve domain names through malicious infrastructure controlled by the attacker. This capability facilitates sophisticated man-in-the-middle attacks where users are silently redirected from legitimate websites to phishing pages or sites hosting malware. The impact extends beyond simple redirection; it compromises the integrity of all DNS queries originating from the affected router, potentially leading to credential theft, financial fraud, and widespread compromise of end-user devices relying on this network for internet connectivity.
This vulnerability aligns with CWE-287, which describes Improper Authentication, as well as CWE-352 regarding Cross-Site Request Forgery (CSRF) principles where state-changing requests are executed without sufficient verification of the user's intent or identity through robust session tokens. In terms of offensive security frameworks such as MITRE ATT&CK, this behavior corresponds to techniques involving credential access and lateral movement via network device manipulation, specifically falling under tactics that allow for traffic interception and redirection. The exploitation does not require complex payload construction beyond manipulating HTTP headers, making it highly accessible to automated scanning tools and script-kiddies alike, thereby increasing the risk of widespread compromise across vulnerable deployments globally.
Mitigation strategies must prioritize immediate firmware updates provided by Tenda if available, as vendors typically address such session validation flaws in subsequent releases. In environments where patching is not immediately feasible, network segmentation should be implemented to isolate management interfaces from untrusted networks, ensuring that administrative ports are only accessible via secure, authenticated channels or dedicated management VLANs. Additionally, deploying intrusion detection systems capable of identifying anomalous HTTP requests targeting configuration endpoints can provide an additional layer of defense against exploitation attempts until the underlying software defect is resolved through official vendor support channels.