CVE-2019-20740 in DGN2200v4
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects DGN2200v4 before 1.0.0.110, DGND2200Bv4 before 1.0.0.109, R7300 before 1.0.0.70, R8300 before 1.0.2.130, and R8500 before 1.0.2.130.
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Analysis
by VulDB Data Team • 05/07/2025
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR networking devices including the DGN2200v4, DGND2200Bv4, R7300, R8300, and R8500 models. The issue stems from inadequate input validation within the device's web interface handling mechanism, specifically when processing user-supplied data through HTTP requests. An authenticated attacker with valid credentials can exploit this vulnerability by sending specially crafted requests that exceed the allocated buffer space on the device's stack memory. The flaw allows for arbitrary code execution and complete system compromise, making it particularly dangerous in networked environments where unauthorized access could lead to widespread security breaches.
The technical implementation of this vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which occurs when a program writes data beyond the boundaries of a fixed-length buffer allocated on the stack. This particular implementation affects the web server component of the affected NETGEAR devices, where user input from HTTP parameters is processed without proper bounds checking. The vulnerability exists in the device's firmware code where string manipulation functions are used without validating input length against buffer capacity, creating a predictable memory corruption scenario that can be exploited through network-based attacks.
The operational impact of this vulnerability extends beyond simple device compromise to encompass complete network infrastructure takeover. An authenticated user can leverage this flaw to execute arbitrary commands on the affected devices, potentially gaining root access to the system. This allows for persistent backdoor establishment, network reconnaissance, and further lateral movement within the compromised network. The vulnerability affects devices running firmware versions prior to the specified patches, indicating that the issue has existed for an extended period without proper mitigation. Attackers could exploit this vulnerability to modify device configurations, install malicious firmware, or redirect network traffic through the compromised devices, creating significant operational disruption and security risks for organizations relying on these networking components.
Mitigation strategies should focus on immediate firmware updates to the latest available versions that contain patches addressing the buffer overflow conditions. Organizations must ensure all affected NETGEAR devices are updated through official channels, as the patches typically include proper input validation and bounds checking mechanisms. Network segmentation and access control measures should be implemented to limit the potential impact of successful exploitation, including restricting administrative access to only trusted users and networks. Additionally, monitoring for unusual network traffic patterns and unauthorized configuration changes can help detect exploitation attempts. The vulnerability highlights the importance of regular firmware updates and security assessments for network infrastructure components, as it represents a common class of vulnerability that affects many embedded systems in the networking industry. Security teams should also consider implementing network-based intrusion detection systems that can identify and block malicious requests attempting to exploit this specific buffer overflow condition.