CVE-2026-17252 in TL-MR6400
Summary
by MITRE • 08/21/2026
A stack-based out-of-bounds write vulnerability exists in the login request handling functionality of the administrative web interface of TP-Link TL-MR6400 v7 routers. An unauthenticated adjacent attacker can trigger the vulnerability by sending a specially crafted malformed HTTP request.
Successful exploitation may cause the web service process to crash, resulting in a denial-of-service condition and temporary loss of access to the router's web management interface.
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Analysis
by VulDB Data Team • 08/21/2026
The TP-Link TL-MR6400 v7 wireless router presents a critical security vulnerability within its administrative web interface, specifically affecting the login request handling mechanism. This flaw is classified as a stack-based out-of-bounds write, which represents a severe memory corruption issue where data written to a buffer exceeds its allocated boundaries on the call stack. The vulnerability arises from insufficient validation of input parameters during the processing of HTTP requests intended for authentication purposes. Because this functionality is exposed through the web server interface, it allows an attacker who has network access to interact directly with the vulnerable code path without needing prior credentials.
An unauthenticated adjacent attacker can exploit this weakness by constructing and transmitting a specially crafted malformed HTTP request designed to trigger the buffer overflow condition. The malicious payload likely involves manipulating specific fields within the login form or headers in a way that causes the underlying C-based application logic to write data beyond the limits of the designated stack variable. This type of exploitation does not require complex privilege escalation techniques initially, as it relies solely on the improper handling of external input by the web service process running on the router firmware.
The immediate operational impact of successfully exploiting this vulnerability is a crash of the web service process responsible for managing administrative access. When the memory corruption occurs, it typically leads to an application fault or segmentation violation, causing the daemon to terminate unexpectedly. This results in a denial-of-service condition where the router's web management interface becomes temporarily inaccessible. While the primary effect described is availability loss rather than remote code execution, such crashes can be leveraged for persistent disruption of network operations and may potentially serve as a precursor to more severe attacks if further memory corruption techniques are applied or if the crash state allows for information leakage that aids in subsequent exploitation attempts.
From a classification perspective, this vulnerability aligns with CWE-121, which denotes stack-based buffer overflow, indicating improper handling of input data leading to writing beyond allocated memory boundaries on the stack. In terms of attack tactics, it corresponds to MITRE ATT&CK techniques related to Initial Access and Impact, specifically focusing on Denial of Service through service disruption. The lack of authentication requirement places this vulnerability in a high-risk category for devices deployed in environments where physical or local network access is possible, such as home networks or small office setups with open Wi-Fi configurations.
Mitigation strategies should prioritize immediate firmware updates provided by TP-Link that address the input validation logic within the web interface's login handler. Administrators must ensure their routers are running the latest stable firmware version to patch this specific memory corruption flaw. In cases where updating is not immediately feasible, network segmentation can help isolate the router from untrusted networks, and disabling remote management features if they are enabled reduces the attack surface by limiting exposure to adjacent attackers who might otherwise gain access through compromised local devices or wireless connections. Regular monitoring of system logs for unexpected service restarts may also aid in detecting attempted exploitation activities before significant disruption occurs.