CVE-2026-71940
Received Received - Intake

Buffer Overflow in DrayTek VigorSwitch via ACL Setup

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 acl_general_setup Edit ACE function. The vulnerability is caused by copying the name field into a fixed-size buffer without length validation. 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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

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-2026-71940
EUVD
EUVD-2026-64999

Affected Vendors & Products

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

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
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.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

CVE-2026-71940 is a buffer overflow vulnerability in multiple DrayTek VigorSwitch models. It occurs in the acl_general_setup Edit ACE function where a fixed-size buffer is filled with user-controlled input without proper length validation. This allows a remote attacker with administrative credentials to cause a denial of service or execute arbitrary code by sending crafted input.

Detection Guidance

Detecting this vulnerability requires checking the firmware version of DrayTek VigorSwitch devices. Compare the installed firmware against the latest versions provided in DrayTek's August 2026 security advisory. Access the device's web management interface and navigate to the firmware information section.

Impact Analysis

If exploited, this vulnerability could allow an attacker to crash the device (denial of service) or run arbitrary commands on it. This requires the attacker to have valid administrative credentials for the device's web management interface. Successful exploitation could lead to unauthorized access, control of the switch, or disruption of network services.

Compliance Impact

This vulnerability could impact compliance with standards like GDPR and HIPAA by potentially allowing unauthorized access to network devices. If exploited, it may lead to data breaches or unauthorized control of network infrastructure, which are critical concerns under these regulations. Administrative credentials are required for exploitation, but successful attacks could compromise device integrity and data confidentiality.

Mitigation Strategies

Immediately update the firmware of all affected DrayTek VigorSwitch models to the latest versions specified in DrayTek's security advisory. Ensure administrative credentials for the web management interface are strong and not shared. Monitor network traffic for unusual activity targeting the switch's web interface.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-71940. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart