CVE-2020-35796

Vulnerability

CVE-2020-35796 is a pre-authentication buffer overflow vulnerability affecting a wide range of NETGEAR routers, range extenders, and WiFi systems. The vulnerability exists in the firmware of the affected devices and can be triggered without authentication. The affected models include CBR40 before 2.5.0.10, D6220 before 1.0.0.60, D6400 before 1.0.0.94, D7000v2 before 1.0.0.62, D8500 before 1.0.3.50, DC112A before 1.0.0.48, DGN2200v4 before 1.0.0.114, EAX20 before 1.0.0.36, EAX80 before 1.0.1.62, EX3700 before 1.0.0.84, EX3800 before 1.0.0.84, EX3920 before 1.0.0.84, EX6000 before 1.0.0.44, EX6100 before 1.0.2.28, EX6120 before 1.0.0.54, EX6130 before 1.0.0.36, EX6150 before 1.0.0.46, EX6200 before 1.0.3.94, EX6920 before 1.0.0.54, EX7000 before 1.0.1.90, EX7500 before 1.0.0.68, MK62 before 1.0.5.102, MR60 before 1.0.5.102, MS60 before 1.0.5.102, R6250 before 1.0.4.42, R6300v2 before 1.0.4.42, R6400 before 1.0.1.62, R6400v2 before 1.0.4.98, R6700v3 before 1.0.4.98, R6700 before 1.0.2.16, R6900P before 1.3.2.124, R6900 before 1.0.2.16, R7000 before 1.0.11.106, R7000P before 1.3.2.124, R7100LG before 1.0.0.56, R7850 before 1.0.5.60, R7900 before 1.0.4.26, R7900P before 1.4.1.62, R7960P before 1.4.1.62, R8000 before 1.0.4.58, R8000P before 1.4.1.62, R8300 before 1.0.2.134, R8500 before 1.0.2.134, RAX15 before 1.0.1.64, RAX20 before 1.0.1.64, RAX200 before 1.0.2.102, RAX45 before 1.0.2.32, RAX50 before 1.0.2.32, RAX75 before 1.0.3.102, RAX80 before 1.0.3.102, RBK752 before 3.2.16.6, RBR750 before 3.2.16.6, RBS750 before 3.2.16.6, RBK842 before 3.2.16.6, RBR840 before 3.2.16.6, RBS840 before 3.2.16.6, RBK852 before 3.2.16.6, RBR850 before 3.2.16.6, RBS850 before 3.2.16.6, RBS40V-200 before 1.0.0.46, RBW30 before 2.5.0.4, RS400 before 1.5.0.48, WN2500RPv2 before 1.0.1.56, WN3500RP before 1.0.0.28, WNDR3400v3 before 1.0.1.32, WNR1000v3 before 1.0.2.78, WNR2000v2 before 1.2.0.12, WNR3500Lv2 before 1.2.0.62, and XR300 before 1.0.3.50 [1].

Exploitation

An unauthenticated attacker can trigger the buffer overflow by sending a specially crafted request to the device. No authentication is required, and the vulnerability may be exploited remotely without user interaction [1]. The attacker must have network access to the target device.

Impact

Successful exploitation of the buffer overflow could allow an attacker to cause a denial of service (device crash) or potentially execute arbitrary code on the device [1]. The impact may include full compromise of the affected device.

Mitigation

NETGEAR has released firmware updates to fix this vulnerability for all listed models. Users should update to the latest firmware version for their specific device as indicated in the security advisory [1]. The fixed versions include CBR40 2.5.0.10, D6220 1.0.0.60, D6400 1.0.0.94, and others [1]. No workarounds have been published. This vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.