DrayTek VigorSwitch Add ACE acl_general_setup Add ACE function Name buffer overflow

Summaryinfo

A vulnerability was found in DrayTek VigorSwitch. It has been declared as very critical. Affected is the function acl_general_setup Add ACE function of the component Add ACE. Such manipulation of the argument Name leads to buffer overflow. This vulnerability is listed as CVE-2026-71939. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in DrayTek VigorSwitch (version now known). Affected by this issue is the function acl_general_setup Add ACE function of the component Add ACE. The manipulation of the argument name with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to 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, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the acl_general_setup Add 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.

The advisory is available at draytek.com. This vulnerability is handled as CVE-2026-71939 since 08/08/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are necessary for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/24/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-64998). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Router Operating System

Vendor

• DrayTek

Name

• VigorSwitch

License

• commercial

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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