CVE-2018-21202

Vulnerability

A stack-based buffer overflow vulnerability exists in certain NETGEAR devices, including D7800, R6100, R7500, R7500v2, R7800, R9000, WNDR3700v4, WNDR4300, WNDR4300v2, and WNDR4500v3. The flaw is triggered during pre-authentication processing, meaning no credentials are required to reach the vulnerable code path. Affected firmware versions are those prior to the following: D7800 before 1.0.1.30, R6100 before 1.0.1.20, R7500 before 1.0.0.118, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.96, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.54, and WNDR4500v3 before 1.0.0.54 [1].

Exploitation

An unauthenticated attacker with network adjacency (e.g., within Wi-Fi range) can send a specially crafted packet to the affected device. The request triggers a stack-based overflow, enabling control of the execution flow. No user interaction or prior authentication is required [1].

Impact

Successful exploitation allows the attacker to execute arbitrary code on the device with elevated privileges, leading to full compromise of confidentiality, integrity, and availability. The CVSS v3 score is 8.8 (High) [1].

Mitigation

NETGEAR has released firmware updates for all affected models. Users should download and install the latest firmware from the NETGEAR Support website as soon as possible. No workarounds are available for devices that remain unpatched [1].