CVE-2026-19844
Received Received - Intake

Stack-Based Buffer Overflow in TOTOLINK A800R Router

Vulnerability report for CVE-2026-19844, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-14

Last updated on: 2026-08-14

Assigner: VulDB

Description

A vulnerability was found in TOTOLINK A800R 4.1.2cu.5137_B20200730. The impacted element is the function setRadvdCfg of the file /cgi-bin/cstecgi.cgi of the component ipv6.so. Performing a manipulation of the argument radvdinterfacename results in stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been made public and could be used.

CVSS Scores

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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
EUVD

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.

Attack-Flow Graph

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Executive Summary

CVE-2026-19844 is a stack-based buffer overflow in TOTOLINK A800R router firmware version 4.1.2cu.5137_B20200730. It occurs in the setRadvdCfg function of the ipv6.so library when the radvdinterfacename parameter is passed to strcpy without bounds checking. An attacker can exploit this by sending a crafted POST request to /cgi-bin/cstecgi.cgi with a long radvdinterfacename value, causing stack overflow.

Detection Guidance

To detect this vulnerability, check if your TOTOLINK A800R router is running firmware version V4.1.2cu.5137_B20200730. Inspect network traffic for POST requests to /cgi-bin/cstecgi.cgi with unusually long radvdinterfacename parameters. Use tools like Wireshark to capture and analyze HTTP requests targeting this endpoint.

Impact Analysis

This vulnerability allows remote attackers to execute arbitrary code or cause denial-of-service on affected TOTOLINK A800R routers. Since the exploit is public, unpatched devices are at high risk of compromise. Attackers could gain control of the router, intercept network traffic, or use it as a foothold for further attacks.

Mitigation Strategies

Immediately update the TOTOLINK A800R firmware to the latest version. If an update is unavailable, disable IPv6 functionality on the router or restrict access to the /cgi-bin/cstecgi.cgi endpoint via firewall rules. Monitor network traffic for suspicious POST requests to this path.

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