CVE-2021-34991: NETGEAR CAX80 Firmware

High severity, CVSS 8.8. EPSS: 5.7% chance of exploitation in the next 30 days.

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400v2 1.0.4.106_10.0.80 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the UPnP service, which listens on TCP port 5000 by default. When parsing the uuid request header, the process does not properly validate the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-14110.

Affected products

• NETGEAR CAX80 Firmware: before 2.1.3.5 (fixed in 2.1.3.5)
• NETGEAR d6220 Firmware: before 1.0.0.76 (fixed in 1.0.0.76)
• NETGEAR d6400 Firmware: before 1.0.0.108 (fixed in 1.0.0.108)
• NETGEAR d7000v2 Firmware: before 1.0.0.76 (fixed in 1.0.0.76)
• NETGEAR DC112A Firmware: before 1.0.0.62 (fixed in 1.0.0.62)
• NETGEAR DGN2200V4 Firmware: before 1.0.0.126 (fixed in 1.0.0.126)
• NETGEAR EX3700 Firmware: before 1.0.0.94 (fixed in 1.0.0.94)
• NETGEAR EX3800 Firmware: before 1.0.0.94 (fixed in 1.0.0.94)
• NETGEAR EX6120 Firmware: before 1.0.0.66 (fixed in 1.0.0.66)
• NETGEAR EX6130 Firmware: before 1.0.0.66 (fixed in 1.0.0.66)
• NETGEAR r6400 Firmware: before 1.0.1.76 (fixed in 1.0.1.76)
• NETGEAR r6400v2 Firmware: before 1.0.4.120 (fixed in 1.0.4.120)
• NETGEAR r6700v3 Firmware: before 1.0.4.120 (fixed in 1.0.4.120)
• NETGEAR r6900p Firmware: before 1.3.3.142 (fixed in 1.3.3.142)
• NETGEAR r7000 Firmware: before 1.0.11.128 (fixed in 1.0.11.128)
• NETGEAR r7000p Firmware: before 1.3.3.142 (fixed in 1.3.3.142)
• NETGEAR r7100lg Firmware: before 1.0.0.72 (fixed in 1.0.0.72)
• NETGEAR r7850 Firmware: before 1.0.5.76 (fixed in 1.0.5.76)
• NETGEAR r7900p Firmware: before 1.4.2.84 (fixed in 1.4.2.84)
• NETGEAR r7960p Firmware: before 1.4.2.84 (fixed in 1.4.2.84)
• NETGEAR r8000 Firmware: before 1.0.4.76 (fixed in 1.0.4.76)
• NETGEAR r8000p Firmware: before 1.4.2.84 (fixed in 1.4.2.84)
• NETGEAR r8300 Firmware: before 1.0.2.156 (fixed in 1.0.2.156)
• NETGEAR r8500 Firmware: before 1.0.2.156 (fixed in 1.0.2.156)
• NETGEAR RAX15 Firmware: before 1.0.4.100 (fixed in 1.0.4.100)
• and 19 more

Published 2021-11-15. Last modified 2026-06-17.