Executive Summary

A critical vulnerability, CVE-2026-94089, has been identified in D-Link DIR-868L version 2.01b05. This vulnerability affects the Authentication Handler component, specifically the /webfa_authentication.cgi file, and allows for a stack-based buffer overflow. The vulnerability has a CVSS score of 10, indicating the highest severity level. Although it is not currently being actively exploited, the exploit has been publicly disclosed.

Technical Analysis

The vulnerability is classified as a stack-based buffer overflow (CWE-119 and CWE-121). It is located in the strcpy function of the /webfa_authentication.cgi file, which is part of the Authentication Handler component. An attacker can manipulate the id and password arguments to trigger the overflow. This vulnerability can be exploited remotely without requiring any user interaction or privileges.

How It Gets Exploited

An unauthenticated remote attacker can send a crafted request to the /webfa_authentication.cgi endpoint with a manipulated id and password argument that exceeds the buffer size. When the strcpy function processes this input, it fails to validate the length, causing a stack-based buffer overflow. This overflow can overwrite critical memory regions, potentially allowing for remote code execution. The attacker gains control over the device, enabling them to execute arbitrary commands.

Impact Assessment

The affected product is D-Link DIR-868L version 2.01b05. An attacker can achieve remote code execution, confidentiality impact, integrity impact, and availability impact, all with high severity. The CVSS score of 10 indicates the highest possible impact.

Recommended Actions

To mitigate this vulnerability, users should update their D-Link DIR-868L devices to a version that is not vulnerable. Although the specific patched version is not provided in the source data, it is recommended to check the D-Link official website for updates or contact their support for guidance. Additionally, blocking unnecessary exposure of the device to the internet and implementing a Web Application Firewall (WAF) can help reduce the risk of exploitation.

Sources

- National Vulnerability Database (NVD) - Vuldb.com