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7.2
HIGH CVSS 4.0
CVE-2026-71938
DrayTek VigorSwitch Multiple Models Buffer Overflow via switch_lan_gvrp
Overview
Description

Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the switch_lan_gvrp function. The vulnerability is caused by unsafe copying of the portList field into an undersized buffer. 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.

Details
INFO

Published Date :

Aug. 24, 2026, 6:17 p.m.

Last Modified :

Aug. 24, 2026, 6:17 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-71938 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Draytek vigorswitch_pq2200xb
2 Draytek vigorswitch_pq2121x
3 Draytek vigorswitch_p2540xs
4 Draytek vigorswitch_p2280x
5 Draytek vigorswitch_p2100
6 Draytek vigorswitch_q2200x
7 Draytek vigorswitch_q2121x
8 Draytek vigorswitch_g2540xs
9 Draytek vigorswitch_g2280x
10 Draytek vigorswitch_g2121
11 Draytek vigorswitch_g2100
12 Draytek vigorswitch_fx2120
13 Draytek vigorswitch_p1282
14 Draytek vigorswitch_g1282
: Total Affected Vendor : 1 | Products : 14
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 HIGH [email protected]
CVSS 3.1 HIGH MITRE-CVE
CVSS 4.0 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 HIGH [email protected]
Solution
Update firmware to patch buffer overflow. Apply vendor security recommendations.
  • Update device firmware to the latest version.
  • Review and apply vendor security advisories.
  • Restrict administrative access to the device.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-71938.

URL Resource
https://www.draytek.com/about/security-advisory/multiple-vulnerabilities-in-vigorswitch-series-august-2026/
https://www.vulncheck.com/advisories/draytek-vigorswitch-multiple-models-buffer-overflow-via-switch-lan-gvrp
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-71938 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-71938 weaknesses.

CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-42: MIME Conversion MIME Conversion CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-92: Forced Integer Overflow Forced Integer Overflow CAPEC-100: Overflow Buffers Overflow Buffers

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-71938 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-71938 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Aug. 24, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G2540xs', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2540xs', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch FX2120', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G2282x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.10.6', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2282x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.10.6', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch Q2300x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.10.7', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch PQ2300xb', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.10.7', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G2542x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.10.6', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2542x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.10.6', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2542xh', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.10.6', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch PX2060', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G1280', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P1280', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P1281x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G1282', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P1282', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G2121', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2121', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch PQ2121x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch Q2121x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G2280x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2280x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch Q2200x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch PQ2200xb', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G2100', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2100', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch G2540x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'DrayTek Corporation', 'product': 'VigorSwitch P2540x', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.9.10', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}]
    Added Description Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the switch_lan_gvrp function. The vulnerability is caused by unsafe copying of the portList field into an undersized buffer. 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.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
    Added CWE CWE-120
    Added Reference https://www.draytek.com/about/security-advisory/multiple-vulnerabilities-in-vigorswitch-series-august-2026/
    Added Reference https://www.vulncheck.com/advisories/draytek-vigorswitch-multiple-models-buffer-overflow-via-switch-lan-gvrp
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 8.6
Attack Vector
Attack Complexity
Attack Requirements
Privileges Required
User Interaction
VS Confidentiality
VS Integrity
VS Availability
SS Confidentiality
SS Integrity
SS Availability
Base CVSS Score: 7.2
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact