CVE-2018-21145

Vulnerability

A stack-based buffer overflow vulnerability exists in the firmware of multiple NETGEAR gateway and router models. The flaw can be triggered by an authenticated user and affects the following devices running firmware versions prior to the indicated fixed releases: D7800 before 1.0.1.34, DM200 before 1.0.0.50, R6100 before 1.0.1.22, R7500 before 1.0.0.122, R7800 before 1.0.2.42, R8900 before 1.0.3.10, R9000 before 1.0.3.10, WNDR3700v4 before 1.0.2.96, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.54, WNDR4500v3 before 1.0.0.54, and WNR2000v5 before 1.0.0.64 [1].

Exploitation

An attacker must first authenticate to the device with valid credentials. After authentication, the attacker can send a specially crafted request that overflows a stack buffer, potentially leading to memory corruption. No additional user interaction or network position beyond network access to the device's management interface is required [1].

Impact

Successful exploitation of the stack overflow could allow an authenticated attacker to execute arbitrary code on the device or cause a denial of service. The exact impact depends on the device model and firmware, but the vulnerability is classified as a stack-based buffer overflow, which typically enables code execution with elevated privileges [1].

Mitigation

NETGEAR has released firmware updates that fix the vulnerability for all affected models. Users should update to the latest firmware version as listed in the Vulnerability section. No workarounds are available; updating is the only mitigation. The vulnerability is not known to be listed in CISA's Known Exploited Vulnerabilities catalog [1].