CVE-2026-71938: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in DrayTek Corporation VigorSwitch G2540xs
A buffer overflow vulnerability exists in the DrayTek VigorSwitch G2540xs in the switch_lan_gvrp function due to unsafe copying of the portList field into an undersized buffer. An attacker with valid administrative credentials can exploit this flaw remotely via the device's web management interface, potentially causing denial of service or arbitrary command execution. The vulnerability has a high severity rating with a CVSS score of 8.6. No patch or official remediation guidance is currently provided by the vendor.
AI Analysis
Technical Summary
CVE-2026-71938 is a classic buffer overflow vulnerability in DrayTek VigorSwitch G2540xs devices. It arises from unsafe copying of the portList field into an undersized buffer within the switch_lan_gvrp function. Exploitation requires valid administrative credentials to the device's web management interface, allowing a remote attacker to trigger the overflow. Successful exploitation could lead to denial of service or arbitrary command execution on the device. The vulnerability is rated high severity with a CVSS 4.0 score of 8.6. No vendor advisory or patch information is currently available.
Potential Impact
The vulnerability allows a remote attacker with administrative credentials to cause denial of service or potentially execute arbitrary commands on the affected device. This could disrupt network operations or compromise device integrity.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict administrative access to trusted personnel and networks to reduce risk.
CVE-2026-71938: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') in DrayTek Corporation VigorSwitch G2540xs
Description
A buffer overflow vulnerability exists in the DrayTek VigorSwitch G2540xs in the switch_lan_gvrp function due to unsafe copying of the portList field into an undersized buffer. An attacker with valid administrative credentials can exploit this flaw remotely via the device's web management interface, potentially causing denial of service or arbitrary command execution. The vulnerability has a high severity rating with a CVSS score of 8.6. No patch or official remediation guidance is currently provided by the vendor.
CVSS v4.0
Score 8.6high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-71938 is a classic buffer overflow vulnerability in DrayTek VigorSwitch G2540xs devices. It arises from unsafe copying of the portList field into an undersized buffer within the switch_lan_gvrp function. Exploitation requires valid administrative credentials to the device's web management interface, allowing a remote attacker to trigger the overflow. Successful exploitation could lead to denial of service or arbitrary command execution on the device. The vulnerability is rated high severity with a CVSS 4.0 score of 8.6. No vendor advisory or patch information is currently available.
Potential Impact
The vulnerability allows a remote attacker with administrative credentials to cause denial of service or potentially execute arbitrary commands on the affected device. This could disrupt network operations or compromise device integrity.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict administrative access to trusted personnel and networks to reduce risk.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-08T16:37:44.519Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a8c7defacd9273b49e1b46c
Added to database: 08/24/2026, 17:22:55 UTC
Last enriched: 08/24/2026, 17:37:33 UTC
Last updated: 08/24/2026, 18:50:00 UTC
Views: 6
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