CVE-2026-121599
Deferred Deferred - Pending Action

Stack-Based Buffer Overflow in TOTOLINK A950RG

Vulnerability report for CVE-2026-121599, 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 vulnerability was detected in TOTOLINK A950RG 4.1.2cu.5268_B20221104. Affected is the function setWiFiMultipleConfig/delWiFiMultipleConfig of the file /cgi-bin/cstecgi.cgi of the component Multi-SSID Configuration. The manipulation of the argument wepkey2/wepkey3 results in stack-based buffer overflow. It is possible to launch the attack remotely. The exploit is now public 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-2026-121599 is a stack-based buffer overflow in TOTOLINK A950RG router version 4.1.2cu.5268_B20221104. The flaw exists in functions handling multi-SSID configurations, where WEP key parameters (wepkey2/wepkey3) are copied into a fixed-size stack buffer without length checks. This allows attackers to overwrite memory, potentially executing arbitrary code remotely.

Detection Guidance

To detect this vulnerability, monitor network traffic for malformed requests targeting /cgi-bin/cstecgi.cgi with excessive wepkey2 or wepkey3 parameters. Use tools like tcpdump or Wireshark to capture and analyze HTTP POST requests to this endpoint. Check for crashes or unusual behavior in the router's logs after sending test payloads.

Impact Analysis

This vulnerability allows remote attackers to execute arbitrary code on the router by sending specially crafted requests. Since the router lacks modern protections like stack canaries or ASLR, exploitation is straightforward. Attackers could gain full control over the device, intercept network traffic, or use it as a pivot point for further attacks.

Mitigation Strategies

Immediately update the TOTOLINK A950RG firmware to the latest version if a patch is available. Disable remote administration and restrict access to the router's web interface. Block external requests to /cgi-bin/cstecgi.cgi at the network perimeter. Monitor for exploit attempts and isolate affected devices if compromised.

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