Title: Tenda A21 V1.0.0.0 Stack-based Buffer Overflow Description: - The vulnerability was found in the MAC filtering configuration endpoint in Tenda A21 router firmware (version V1.0.0.0). - It occurs within the function called by the primary request handler . - The function uses unsanitized user-supplied and parameters to store device information using the unsafe function. - It leads to a stack buffer overflow in a fixed-size buffer ( , 256 bytes). - An attacker can exploit this by providing a long value, corrupting the stack and gaining control over the instruction pointer. Source: https://github.com/QIU-DIE/cve-nneeww/issues/3 User: hhsn34 (UID 91076) Submission Date: 02/09/2026 Moderation Date: 02/20/2026 Status: Accepted VulDB Entry: 237109 [Tenda A21 1.0.0.0 MAC Filtering Configuration Endpoint /goform/setBlackRule set_device_name devName/mac stack-based overflow] Points: 20