CVE-2026-19815
Received Received - Intake

Stack-Based Buffer Overflow in TOTOLINK A800R Router

Publication date: 2026-08-14

Last updated on: 2026-08-14

Assigner: VulDB

Description
A flaw has been found in TOTOLINK A800R 4.1.2cu.5137_B20200730. Affected by this vulnerability is the function setParentalRules of the file /cgi-bin/cstecgi.cgi of the component firewall.so. Executing a manipulation of the argument urlKeyword can lead to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been published and may be used.

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Meta Information

Published
2026-08-14
Last Modified
2026-08-14
Generated
2026-08-14
AI Q&A
2026-08-14
EPSS Evaluated
N/A
NVD
CVE-2026-19815
EUVD
EUVD-2026-58613

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
totolink a800r 4.1.2cu.5137_b20200730

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.

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Executive Summary

CVE-2026-19815 is a stack-based buffer overflow vulnerability in the TOTOLINK A800R router firmware version V4.1.2cu.5137_B20200730. It exists in the setParentalRules function of the firewall.so component. The flaw occurs because the urlKeyword parameter from user requests is passed directly to the sprintf function without proper bounds checking, allowing a stack overflow.

Detection Guidance

Check if your TOTOLINK A800R router is running firmware version V4.1.2cu.5137_B20200730. Inspect network traffic for HTTP POST requests targeting /cgi-bin/cstecgi.cgi with the setParentalRules parameter. Look for unusual stack overflow patterns or crashes in the firewall.so component.

Impact Analysis

This vulnerability can be exploited remotely by sending a crafted HTTP POST request to the vulnerable endpoint. It may allow an attacker to execute arbitrary code or cause a denial of service on the affected router. Since a proof-of-concept has been publicly disclosed, the risk of exploitation is increased.

Compliance Impact

This vulnerability could lead to unauthorized code execution or denial of service, potentially exposing sensitive data or disrupting critical services. For GDPR, it may result in unauthorized access to personal data, violating confidentiality requirements. For HIPAA, it could compromise protected health information integrity or availability.

Mitigation Strategies

Update the router firmware to the latest version if available. Disable remote access to the router's web interface if not required. Block suspicious HTTP POST requests to /cgi-bin/cstecgi.cgi at the network perimeter. Monitor for unusual activity or crashes in the firewall component.

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