CVE-2026-121598
Deferred Deferred - Pending Action

Stack-Based Buffer Overflow in TOTOLINK A950RG Router

Vulnerability report for CVE-2026-121598, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-11-04

Last updated on: 2026-11-04

Assigner: VulDB

Description

A security vulnerability has been detected in TOTOLINK A950RG 4.1.2cu.5268_B20221104. This impacts the function strcpy of the file /cgi-bin/cstecgi.cgi of the component Basic Wireless Configuration Handler. The manipulation of the argument wepkey leads to stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been disclosed publicly and may be used.

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Meta Information

Published
2026-11-04
Last Modified
2026-11-04
Generated
2026-11-04
AI Q&A
2026-11-04
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
TOTOLINK A950RG 4.1.2cu.5268_B20221104

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-121 A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
CWE-119 The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

Attack-Flow Graph

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Executive Summary

CVE-2026-121598 is a stack-based buffer overflow in TOTOLINK A950RG firmware version 4.1.2cu.5268_B20221104. The vulnerability occurs in the Basic Wireless Configuration Handler component, specifically in the strcpy function of /cgi-bin/cstecgi.cgi when processing the wepkey argument. Due to lack of input validation, an attacker can overflow a 68-byte stack buffer, potentially overwriting the return address and executing arbitrary code.

Detection Guidance

To detect this vulnerability, inspect network traffic for malformed requests targeting /cgi-bin/cstecgi.cgi with excessive wepkey parameter lengths. Use tools like Wireshark to capture and analyze HTTP POST requests to this endpoint. Check router logs for crashes or unusual activity in the wireless configuration module.

Impact Analysis

This vulnerability allows remote attackers to execute arbitrary code on the affected router. Successful exploitation could lead to full device compromise, unauthorized access to network traffic, or turning the router into a botnet node. Attackers may gain control over the device's settings, intercept sensitive data, or use it as a pivot point to attack other systems on the network.

Mitigation Strategies

Immediately update the router firmware to the latest version if available. Disable WEP encryption and switch to WPA3. Restrict access to the router's management interface via LAN or VPN. Monitor for suspicious activity and consider isolating the device from critical network segments.

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