Attack Chain

1. Initial Access: An attacker identifies a Tenda BE12 Pro router running vulnerable firmware version 16.03.66.23, accessible from the internet.
2. Vulnerability Discovery: The attacker leverages publicly available information or exploit code for CVE-2026-15691, targeting the /goform/SafeClientFilter endpoint.
3. Crafted HTTP Request: The attacker constructs and sends a malicious HTTP request (GET or POST) to the /goform/SafeClientFilter URI on the target router.
4. Argument Manipulation: The crafted request includes a specially formed or excessively long value for the page argument, designed to exceed the allocated buffer size.
5. Buffer Overflow Trigger: The router's fromSafeClientFilter function attempts to process the manipulated page argument, resulting in a stack-based buffer overflow.
6. Arbitrary Code Execution: The overflow is exploited to overwrite the stack with attacker-controlled data, enabling the injection and execution of arbitrary code with the privileges of the affected process.
7. Device Compromise: Upon successful code execution, the attacker gains full control over the router, which can then be used for network reconnaissance, data exfiltration, or as a pivot point for further attacks on the internal network.

Impact

A successful exploitation of CVE-2026-15691 allows for remote code execution on the affected Tenda BE12 Pro router. This means an attacker can gain full control over the device. The impact includes potential unauthorized access to the router's configuration, modification of network settings (such as DNS servers or firewall rules), redirection of network traffic, or the establishment of a persistent backdoor. Compromised routers can serve as a beachhead for attackers to infiltrate the internal network, intercept sensitive data, or launch further attacks against connected devices and services, posing a significant risk to the confidentiality, integrity, and availability of network resources.

Recommendation

• Patch CVE-2026-15691 immediately: Update Tenda BE12 Pro routers to a patched firmware version as soon as one becomes available from the vendor.
• Implement network segmentation: Isolate network infrastructure devices, including routers, into dedicated network segments to limit potential lateral movement if compromised.
• Restrict administrative access: Ensure that Tenda BE12 Pro routers are not directly exposed to the internet via their administrative interfaces; place them behind a firewall and restrict management access to trusted IP ranges.