CVE-2026-71938

EUVD-2026-64997

24.08.2026, 18:17

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.

Classic Buffer Overflow

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	7.2 HIGH	NETWORK	LOW	HIGH	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Awaiting analysis

This vulnerability is currently awaiting analysis.

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Common Weakness Enumeration

CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
The program 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, leading to a buffer overflow.

References

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