What’s Vulnerable › Vulnerabilities
CVE-2021-27239
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.8% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-03-29 · updated 2026-06-17
- Weakness: CWE-121
Description
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: 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; before 1.0.4.102 — fixed in 1.0.1.68, 1.0.4.102
- NETGEAR R6700: 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: before 1.0.11.116 — fixed in 1.0.11.116
- NETGEAR R7000P: 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
- NETGEAR Rax80 Firmware: before 1.0.3.102 — fixed in 1.0.3.102
- NETGEAR Rbr750 Firmware: before 3.2.17.12 — fixed in 3.2.17.12
- NETGEAR Rbr850 Firmware: before 3.2.17.12 — fixed in 3.2.17.12
- NETGEAR Rbs40V Firmware: before 2.6.2.4 — fixed in 2.6.2.4
- Netgear Orbi Satellite RBS750: before 3.2.17.12 — fixed in 3.2.17.12
How to fix
Upgrade to a fixed version: NETGEAR D6220 Firmware 1.0.0.68; Netgear D6400 1.0.0.102; NETGEAR D7000 Firmware 1.0.0.66; NETGEAR D8500 Firmware 1.0.3.60; NETGEAR Dc112A Firmware 1.0.0.54; NETGEAR Ex7000 Firmware 1.0.1.94; NETGEAR Ex7500 Firmware 1.0.0.72; NETGEAR R6250 Firmware 1.0.4.48; NETGEAR R6300 Firmware 1.0.4.50; NETGEAR R6400 Firmware 1.0.1.68, 1.0.4.102; NETGEAR R6700 1.0.4.102; NETGEAR R6900P Firmware 1.3.2.132. Check the vendor advisory for mitigations.
References
- https://kb.netgear.com/000062820/Security-Advisory-for-Stack-based-Buffer-Overflow-Remote-Code-Execution-Vulnerability-on-Some-Routers-PSV-2020-0432
- https://www.zerodayinitiative.com/advisories/ZDI-21-206/
- https://kb.netgear.com/000062820/Security-Advisory-for-Stack-based-Buffer-Overflow-Remote-Code-Execution-Vulnerability-on-Some-Routers-PSV-2020-0432
- https://www.zerodayinitiative.com/advisories/ZDI-21-206/
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