CVE-2026-77946
Received Received - Intake

Stack-Based Buffer Overflow in TRENDnet TEW-821DAP Firmware

Vulnerability report for CVE-2026-77946, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-22

Last updated on: 2026-08-22

Assigner: VulDB

Description

A vulnerability was determined in TRENDnet TEW-821DAP 2.2.01b05. Affected by this vulnerability is the function uci_safe_get of the file /cgi-bin/apply_time.cgi of the component NTP Timezone Configuration Handler. Executing a manipulation of the argument system.ntp.server/system.ntp.enable_server/cameo.time.time_zone/cameo.cameo.syslog_server can lead to stack-based buffer overflow. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized.

CVSS Scores

EPSS Scores

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Meta Information

Published
2026-08-22
Last Modified
2026-08-22
Generated
2026-08-22
AI Q&A
2026-08-22
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
trendnet tew-821dap 2.2.01b05

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

This is a stack-based buffer overflow vulnerability in TRENDnet TEW-821DAP firmware v2.2.01b05. It exists in the NTP and timezone configuration handler of the cgi/ssi binary. User-supplied values like system.ntp.server are copied into fixed-size stack buffers using unsafe strcpy() without bounds checking. Attackers can send oversized values to overwrite the return address, enabling arbitrary code execution with root privileges.

Detection Guidance

To detect this vulnerability, check if your TRENDnet TEW-821DAP device is running firmware version 2.2.01b05. Scan for open ports 80 or 443 on the device's IP address. Send crafted HTTP requests to /cgi-bin/apply_time.cgi with oversized parameters like system.ntp.server to observe crashes or unexpected behavior.

Impact Analysis

An unauthenticated attacker can remotely crash the device or execute arbitrary code with root privileges. This could lead to complete device compromise, unauthorized access, or denial of service. The attack is possible over LAN or WAN if the management interface is exposed.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, violating confidentiality requirements in GDPR and HIPAA. Compromised devices may expose sensitive network traffic or stored data, resulting in non-compliance with data protection regulations.

Mitigation Strategies

Immediately update the device firmware to a patched version if available. Disable remote management access to the web interface. Block external access to /cgi-bin/apply_time.cgi via firewall rules. Monitor device logs for unusual activity or crashes.

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EPSS Chart