CVE-2026-2886 Details

A stack-based buffer overflow vulnerability has been identified in the Tenda A21 router, specifically in the firmware version 1.0.0.0. The issue arises in the `set_device_name` function within the `/goform/SetOnlineDevName` endpoint. The vulnerability is triggered by manipulating the `devName` parameter, which is not properly validated before being used in a `sprintf` function. This oversight allows for the overflow of a fixed-size stack buffer, potentially leading to arbitrary code execution with root privileges. Additionally, the vulnerability can cause a denial-of-service by crashing the `httpd` process, which manages the web interface.

It is recommended to replace unsafe functions like `sprintf` with `snprintf` to prevent buffer overflows. Additionally, implementing strict input validation on the `devName` parameter can help mitigate this vulnerability.