CVE-2026-71937
Received Received - Intake

Buffer Overflow in DrayTek VigorSwitch via poe_schedule_profile

Publication date: 2026-08-24

Last updated on: 2026-08-24

Assigner: VulnCheck

Description
Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the poe_schedule_profile function. The vulnerability is caused by repeated concatenation of the start_date, start_time, duration_time, how_often, weekdays, monthly_date, and cycle_duration fields into small fixed-size buffers without proper length checks. A remote attacker can trigger this vulnerability via crafted input, causing a denial of service or potentially executing arbitrary commands. Exploitation requires valid administrative credentials for the device's web management interface.

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Meta Information

Published
2026-08-24
Last Modified
2026-08-24
Generated
2026-08-24
AI Q&A
2026-08-24
EPSS Evaluated
N/A
NVD
CVE-2026-71937
EUVD
EUVD-2026-64996

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
draytek vigorswitch *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-120 The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

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Executive Summary

This is a buffer overflow vulnerability in multiple DrayTek VigorSwitch models. It occurs in the poe_schedule_profile function where input fields like start_date and start_time are repeatedly concatenated into small fixed-size buffers without proper length checks. A remote attacker with admin credentials could exploit this to cause a denial of service or execute arbitrary commands.

Detection Guidance

Detecting this vulnerability requires checking for affected DrayTek VigorSwitch models and verifying firmware versions. Inspect device models in your network inventory and compare against the list of affected VigorSwitch G, P, Q, FX, and PQ series devices. Check firmware versions via the web management interface or CLI. No specific commands are provided in the context for direct exploitation detection.

Impact Analysis

If exploited, this vulnerability could allow an attacker to crash the device (denial of service) or run malicious commands with administrative privileges. This requires valid admin access to the device's web interface, limiting the attack surface to authorized users or those who have compromised credentials.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by allowing unauthorized access to network devices if exploited. A buffer overflow leading to arbitrary command execution may enable attackers to bypass security controls, access sensitive data, or disrupt operations, which are critical violations under these regulations.

Mitigation Strategies

Immediately update affected DrayTek VigorSwitch devices to the latest firmware versions that address this vulnerability. Ensure administrative credentials for the web management interface are strong and not shared. Restrict access to the device's web interface to trusted networks or IP addresses. Monitor for unusual activity or unauthorized changes.

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