The vulnerability CVE-2026-5830 affects Tenda AC15 firmware version 15.03.05.18. It is a stack-based buffer overflow triggered by improper handling of the oldPwd, newPwd, and cfmPwd arguments in the websGetVar function of the /goform/SysToolChangePwd file. This flaw allows remote attackers to cause a buffer overflow condition, potentially leading to arbitrary code execution or denial of service. The vulnerability has a CVSS 4.0 base score of 8.7, indicating high severity with network attack vector, low complexity, no user interaction, and high impact on confidentiality, integrity, and availability. No vendor patch or official remediation has been documented.

Successful exploitation of this vulnerability can lead to remote code execution or denial of service on the affected device. Given the high CVSS score and the nature of the buffer overflow, attackers could compromise the router's firmware, potentially gaining control over the device or disrupting its operation. The vulnerability requires only low privileges and no user interaction, increasing the risk of exploitation. However, there are no confirmed reports of active exploitation in the wild.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, it is recommended to restrict remote access to the affected endpoint and monitor for unusual activity. Avoid exposing the management interface to untrusted networks. Follow vendor channels for updates regarding patches or official mitigations.