CVE-2018-21186

Vulnerability

A stack-based buffer overflow vulnerability exists in the firmware of multiple NETGEAR routers and gateways. The flaw is triggered when an authenticated user sends a specially crafted request, leading to memory corruption. Affected devices include D7800 before 1.0.1.30, R6100 before 1.0.1.20, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.92, WNDR4300 before 1.0.2.94, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62 [1].

Exploitation

An attacker must be an authenticated user on the same adjacent network as the target device (CVSS:3.0/AV:A/AC:L/PR:H/UI:N). No user interaction is required beyond authentication. The attacker sends a malicious input that overflows a stack buffer, potentially overwriting critical data or control flow structures [1].

Impact

Successful exploitation allows the attacker to achieve arbitrary code execution with elevated privileges, leading to full compromise of confidentiality, integrity, and availability (CVSS v3 Score: 6.8, Medium). The attacker can execute arbitrary commands, modify device configuration, or disrupt normal operation [1].

Mitigation

NETGEAR has released fixed firmware versions for all affected models. Users should upgrade to the latest firmware as soon as possible: D7800 to 1.0.1.30, R6100 to 1.0.1.20, R7500v2 to 1.0.3.24, R7800 to 1.0.2.40, R9000 to 1.0.2.52, WNDR3700v4 to 1.0.2.92, WNDR4300 to 1.0.2.94, WNDR4300v2 to 1.0.0.50, WNDR4500v3 to 1.0.0.50, and WNR2000v5 to 1.0.0.62 [1]. No workarounds are available; applying the firmware update is the only mitigation.