CVE-2021-27252: (Pwn2Own) NETGEAR R7800 udchpd DHCP_REQUEST Command Injection Remote Code Execution Vulnerability

Published Apr 14, 2021
·
Updated

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R7800 firmware version 1.0.2.76. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of the vendorspecific DHCP opcode. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-12216.

Other sources

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R7800. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of the vendorspecific DHCP opcode. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of root.

Affected Software

87 affected components
Netgear R7800
Netgear Br200 Firmware<5.10.0.5
Netgear Br200
Netgear Br500 Firmware<5.10.0.5
Netgear Br500
Netgear D7800 Firmware<1.0.1.60
Netgear D7800
Netgear Ex6100v2 Firmware<1.0.1.98
Netgear EX6100=v2
Netgear Ex6150 Firmware<1.0.1.98
Netgear EX6150=v2
Netgear Ex6250 Firmware<1.0.0.134
Netgear EX6250
Netgear Ex6400 Firmware<1.0.2.158
Netgear EX6400
Netgear Ex6400v2 Firmware<1.0.0.134
Netgear EX6400=v2
Netgear Ex6410 Firmware<1.0.0.134
Netgear EX6410
Netgear Ex6420 Firmware<1.0.0.134
Netgear EX6420
Netgear Ex7300 Firmware<1.0.2.158
Netgear EX7300
Netgear Ex7300v2 Firmware<1.0.0.134
Netgear EX7300=v2
Netgear Ex7320 Firmware<1.0.0.134
Netgear EX7320
Netgear Ex7700 Firmware<1.0.0.216
Netgear EX7700
Netgear Ex8000 Firmware<1.0.1.232
Netgear EX8000
Netgear Lbr20 Firmware<2.6.3.50
Netgear LBR20
Netgear R7800 firmware<1.0.2.80
Netgear R7800
Netgear R8900 Firmware<1.0.5.28
Netgear R8900
Netgear R9000 Firmware<1.0.5.28
Netgear R9000
Netgear Rbk12 Firmware<2.7.2.104
Netgear RBK12
Netgear Rbk13 Firmware<2.7.2.104
Netgear RBK13
Netgear Rbk14 Firmware<2.7.2.104
Netgear RBK14
Netgear Rbk15 Firmware<2.7.2.104
Netgear RBK15
Netgear Rbk20 Firmware<2.6.2.104
Netgear RBK20
Netgear Rbk23 Firmware<2.7.2.104
Netgear RBK23
Netgear Rbk40 Firmware<2.6.2.104
Netgear RBK40
Netgear Rbk43 Firmware<2.6.2.104
Netgear Rbk43
Netgear Rbk43s Firmware<2.6.2.104
Netgear Rbk43s
Netgear Rbk44 Firmware<2.6.2.104
Netgear Rbk44
Netgear Rbk50 Firmware<2.7.2.104
Netgear RBK50
Netgear Rbk53 Firmware<2.7.2.104
Netgear Rbk53
Netgear Rbr10 Firmware<2.6.2.104
Netgear RBR10
Netgear Rbr20 Firmware<2.6.2.104
Netgear RBR20
Netgear Rbr40 Firmware<2.6.2.104
Netgear RBR40
Netgear Rbr50 Firmware<2.7.2.104
Netgear RBR50
Netgear Rbs10 Firmware<2.6.2.104
Netgear RBS10
Netgear Rbs20 Firmware<2.6.2.104
Netgear RBS20
Netgear Rbs40 Firmware<2.6.2.104
Netgear RBS40
Netgear Rbs50 Firmware<2.7.2.104
Netgear RBS50
Netgear Rbs50y Firmware<2.6.2.104
Netgear RBS50Y
Netgear Xr450 Firmware<2.3.2.114
Netgear XR450
Netgear Xr500 Firmware<2.3.2.114
Netgear XR500
Netgear Xr700 Firmware<1.0.1.38
Netgear XR700

Event History

Apr 14, 2021
CVE Published
via MITRE·03:45 PM
Data Sourced
via MITRE·03:45 PM
DescriptionSeverityWeakness
Feb 23, 2025
Advisory Published
via ZDI·03:37 PM
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2021-27252?

CVE-2021-27252 is considered a critical vulnerability as it allows unauthenticated network-adjacent attackers to execute arbitrary code.

2

How do I fix CVE-2021-27252?

To mitigate CVE-2021-27252, upgrade your NETGEAR R7800 firmware to the latest version, specifically 1.0.2.80 or later.

3

Which devices are affected by CVE-2021-27252?

CVE-2021-27252 specifically affects NETGEAR R7800 firmware version 1.0.2.76 and earlier.

4

Is authentication required to exploit CVE-2021-27252?

No, authentication is not required to exploit CVE-2021-27252, making it particularly dangerous.

5

What is the nature of the vulnerability in CVE-2021-27252?

The vulnerability in CVE-2021-27252 is due to improper handling of vendor-specific DHCP messages.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203