CVE-2021-27239: NETGEAR d6220 Firmware

High severity, CVSS 8.8. EPSS: 0.7% chance of exploitation in the next 30 days.

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.

Affected products

NETGEAR d6220 Firmware: before 1.0.0.68 (fixed in 1.0.0.68)
NETGEAR d6400 Firmware: before 1.0.0.102 (fixed in 1.0.0.102)
NETGEAR d7000 Firmware: before 1.0.0.66 (fixed in 1.0.0.66)
NETGEAR d8500 Firmware: before 1.0.3.60 (fixed in 1.0.3.60)
NETGEAR DC112A Firmware: before 1.0.0.54 (fixed in 1.0.0.54)
NETGEAR EX7000 Firmware: before 1.0.1.94 (fixed in 1.0.1.94)
NETGEAR EX7500 Firmware: before 1.0.0.72 (fixed in 1.0.0.72)
NETGEAR r6250 Firmware: before 1.0.4.48 (fixed in 1.0.4.48)
NETGEAR r6300 Firmware: before 1.0.4.50 (fixed in 1.0.4.50)
NETGEAR r6400 Firmware: before 1.0.1.68 (fixed in 1.0.1.68); before 1.0.4.102 (fixed in 1.0.4.102)
NETGEAR r6700 Firmware: before 1.0.4.102 (fixed in 1.0.4.102)
NETGEAR r6900p Firmware: before 1.3.2.132 (fixed in 1.3.2.132)
NETGEAR r7000 Firmware: before 1.0.11.116 (fixed in 1.0.11.116)
NETGEAR r7000p Firmware: before 1.3.2.132 (fixed in 1.3.2.132)
NETGEAR r7100lg Firmware: before 1.0.0.64 (fixed in 1.0.0.64)
NETGEAR r7850 Firmware: before 1.0.5.68 (fixed in 1.0.5.68)
NETGEAR r7900 Firmware: before 1.0.4.38 (fixed in 1.0.4.38)
NETGEAR r7900p Firmware: before 1.4.1.68 (fixed in 1.4.1.68)
NETGEAR r7960p Firmware: before 1.4.1.68 (fixed in 1.4.1.68)
NETGEAR r8000 Firmware: before 1.0.4.68 (fixed in 1.0.4.68)
NETGEAR r8000p Firmware: before 1.4.1.68 (fixed in 1.4.1.68)
NETGEAR r8300 Firmware: before 1.0.2.144 (fixed in 1.0.2.144)
NETGEAR r8500 Firmware: before 1.0.2.144 (fixed in 1.0.2.144)
NETGEAR RAX200 Firmware: before 1.0.2.88 (fixed in 1.0.2.88)
NETGEAR RAX75 Firmware: before 1.0.3.102 (fixed in 1.0.3.102)
and 10 more

Published 2021-03-29. Last modified 2026-06-17.