CVE-2018-21191

Vulnerability

A stack-based buffer overflow vulnerability exists in certain NETGEAR routers and gateways when an authenticated user sends a specially crafted request. The affected models and fixed firmware versions are: D6100 before 1.0.0.57, R6100 before 1.0.1.20, R7800 before 1.0.2.40, 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]. The issue is identified as PSV-2017-2604 [1].

Exploitation

To exploit this vulnerability, an attacker must first authenticate to the device's administrative interface. The attacker then sends a maliciously crafted request that triggers a stack-based buffer overflow. No user interaction beyond authentication is required, and the attack vector is adjacent network (AV:A) with low complexity (AC:L) [1].

Impact

Successful exploitation could allow an authenticated attacker to cause a denial of service or potentially execute arbitrary code with elevated privileges. The CVSS v3 base score is 6.8 (Medium) with a vector of AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating high impact to confidentiality, integrity, and availability [1].

Mitigation

NETGEAR has released fixed firmware versions for all affected models as listed in the Vulnerability section. Users should download and install the latest firmware for their device from the NETGEAR Support website as soon as possible [1]. No workaround is provided; applying the firmware update is the only recommended mitigation.