CVE-2018-21149

Vulnerability

A stack-based buffer overflow vulnerability exists in the firmware of certain NETGEAR devices. The affected models and their respective fixed firmware versions are: 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 1.0.0.54, WNDR4300v2 before 1.0.0.54, WNDR4500v3 before 1.0.0.54, and WNR2000v5 before 1.0.0.64 [1]. The vulnerability is triggered after authentication, requiring valid credentials to access the vulnerable code path.

Exploitation

An attacker must first authenticate to the affected device, then send specially crafted input that overflows a stack buffer. No further user interaction is required beyond the initial authenticated session. The advisory does not detail the exact input vector, but the overflow occurs within the device's web or management interface after authentication [1].

Impact

Successful exploitation could crash the device (denial of service) or potentially allow arbitrary code execution at the system level. The precise impact depends on the attacker's ability to control the overflowed data, though the advisory indicates this is a stack-based buffer overflow, which typically leads to control-flow hijacking [1].

Mitigation

NETGEAR has released fixed firmware versions for all affected models as listed in the Vulnerability section. Users should update to the latest firmware immediately via the NETGEAR Support site [1]. No workarounds are provided; the only mitigation is applying the firmware update.