An input validation flaw permits attackers to control the nptr parameter, which is passed to getMibPrefix and concatenated via sprintf without size checks, leading to a classic buffer overflow in Tenda W20E firmware. This flaw allows the attacker to overflow the stack, potentially executing arbitrary code or causing a denial of service. The vulnerability is rooted in improper bounds checking (CWE-120).

The affected product is the Tenda W20E model running firmware version 4.0br_V15.11.0.6. No other vendors or revisions are listed. The CPE identifiers point to the hardware and firmware versions described above.

The CVSS score of 9.8 indicates critical severity, while the EPSS score of less than 1% signals a low probability of current exploitation. It is not listed in CISA's KEV catalog, yet the high base score warrants proactive remediation. Attackers can likely exploit the flaw over the network by sending crafted packets or HTTP requests that trigger the vulnerable getMibPrefix call, provided the device is reachable and remote management is enabled (based on the description, this is inferred).