CVE-2026-101081 in DI-8400
Summary
by MITRE • 09/28/2026
A security flaw has been discovered in D-Link DI-8400 16.07. This vulnerability affects the function menu_nat_more_asp of the file menu_nat_more.asp of the component Web Administration Service. The manipulation of the argument opt results in stack-based buffer overflow. The attack can be launched remotely. The exploit has been released to the public and may be used for attacks.
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Analysis
by VulDB Data Team • 09/28/2026
The D-Link DI-8400 router, specifically running firmware version 16.07, contains a critical security vulnerability within its Web Administration Service component that allows for remote code execution through a stack-based buffer overflow. This flaw is located in the menu_nat_more.asp file and is triggered by the function menu_nat_more_asp when processing user-supplied input via the opt argument. The underlying technical issue stems from insufficient bounds checking on this specific parameter, which permits an attacker to write more data into a fixed-size memory buffer than it can hold. When the overflow occurs, the excess data overwrites adjacent memory locations on the stack, including critical control structures such as the return address and saved frame pointer. This corruption allows for arbitrary code execution if the overwritten return address points to shellcode injected by the attacker or utilizes Return-Oriented Programming (ROP) techniques to chain existing executable instructions within the binary.
From a classification perspective, this vulnerability aligns with CWE-120, which describes buffer copy without checking size limits, and specifically manifests as a stack-based overflow rather than heap corruption due to its location in local variables on the call stack. In terms of adversary behavior mapping under the MITRE ATT&CK framework, this flaw facilitates initial access through remote exploitation (T1190) and enables privilege escalation if the web service runs with elevated system privileges, which is common for administrative interfaces on embedded devices. The vulnerability also relates to CWE-787, as it involves out-of-bounds write operations that compromise memory integrity. Because the Web Administration Service typically listens on standard HTTP or HTTPS ports accessible from external networks, particularly when port forwarding rules are misconfigured or default credentials remain unchanged, the attack surface is significantly expanded beyond local network boundaries.
The operational impact of this vulnerability is severe, as it grants an unauthenticated remote attacker full control over the compromised device. Once exploited, the attacker can execute arbitrary commands with the privileges of the web server process, which often includes root-level access on embedded Linux systems like those found in D-Link routers. This capability allows for comprehensive network compromise, including interception of traffic, installation of persistent backdoors such as Mirai variants or cryptominers, and use of the device as a pivot point to attack other internal assets. The fact that an exploit has been publicly released increases the risk profile substantially, enabling automated scanning tools and less sophisticated threat actors to target vulnerable instances at scale without needing custom development skills.
Mitigation strategies must address both immediate remediation and long-term security posture improvements. The primary defense is applying the latest firmware update provided by D-Link, which should contain a patch that validates input length for the opt parameter before processing it in menu_nat_more_asp. If an official patch is unavailable or delayed, administrators should restrict access to the Web Administration interface by disabling remote management features and ensuring the administrative port is not exposed to the internet via NAT rules. Additionally, implementing network segmentation can limit lateral movement if a device is compromised. Security monitoring solutions should be configured to detect anomalous HTTP requests containing unusually long strings in query parameters or POST bodies targeting ASP files associated with router configuration pages. Regular audits of connected devices and enforcement of strong authentication policies further reduce the likelihood of successful exploitation by reducing the attack surface available to potential adversaries.