CVE-2026-41223 in Totolink
Summary
by MITRE • 10/20/2026
A stack-based buffer overflow vulnerability exists in the boa formMapDelDevice macstr functionality of X2000R (version(s): TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327). A specially crafted HTTP request can lead to arbitrary code execution. An attacker can make an authenticated HTTP request to trigger this vulnerability.
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Analysis
by VulDB Data Team • 10/20/2026
The TOTOLINK X2000R router, specifically firmware version TOTOLINK-X2000R-Gh-V1.0.0-B20250421.1327, contains a critical stack-based buffer overflow vulnerability within the boa web server's formMapDelDevice function. This flaw is located in the handling of the macstr parameter during device deletion operations. The underlying technical defect stems from insufficient bounds checking when processing user-supplied input for MAC addresses. When an attacker provides a string that exceeds the allocated stack memory size, the application fails to truncate or validate the length before copying it into a fixed-size buffer. This lack of proper boundary validation allows data to spill over adjacent memory locations on the call stack, potentially overwriting critical control data such as return addresses and saved frame pointers.
This vulnerability is classified under CWE-121, which denotes a stack-based buffer overflow. The operational impact of this flaw is severe because it enables an authenticated attacker to achieve arbitrary code execution with the privileges of the web server process. Since the boa web server typically runs with elevated permissions on embedded Linux devices like routers, successful exploitation can lead to full device compromise. An attacker does not need physical access or network-level elevation beyond being able to send HTTP requests; however, authentication is required as per the vulnerability description. This means that if an attacker has obtained valid credentials through phishing, credential stuffing, or other means, they can exploit this flaw remotely over the local area network or potentially via port forwarding if exposed.
The exploitation vector aligns with MITRE ATT&CK technique T1059, specifically command scripting or execution of system commands, as buffer overflow exploits on embedded devices often aim to spawn reverse shells or execute arbitrary binaries like /bin/sh. The attacker crafts a specially formatted HTTP request where the macstr field contains shellcode followed by padding and an overwritten return address pointing back into the injected payload or a gadget within the binary for Return-Oriented Programming (ROP). This allows the execution of malicious instructions, bypassing standard security controls that might otherwise prevent direct code injection.
Mitigation strategies should prioritize immediate firmware updates provided by TOTOLINK if available, as vendors typically release patches to address such critical memory corruption issues. In cases where patching is not immediately possible, network segmentation and strict access control lists can limit exposure to authenticated users only. Additionally, implementing input validation at the gateway or firewall level to detect abnormally long HTTP parameters may provide a layer of defense in depth. Developers should enforce strict length checks on all user inputs before processing them within C-based embedded applications, ensuring that buffer sizes are respected and null-termination is handled correctly to prevent stack corruption.