CVE-2023-43886 in RX9 Pro
Summary
by MITRE • 11/07/2023
A buffer overflow in the HTTP server component of Tenda RX9 Pro v22.03.02.20 might allow an authenticated attacker to overwrite memory.
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Analysis
by VulDB Data Team • 02/08/2026
The vulnerability identified as CVE-2023-43886 represents a critical buffer overflow flaw within the HTTP server component of Tenda RX9 Pro routers running firmware version v22.03.02.20. This issue stems from improper input validation mechanisms that fail to adequately check the length of data received through HTTP requests. The flaw exists in the router's web interface handling code where user-supplied data is processed without sufficient bounds checking, creating a condition where maliciously crafted input can exceed the allocated buffer space. Such buffer overflow conditions typically occur when programs write more data to a fixed-length buffer than it can accommodate, leading to memory corruption that can be exploited by attackers to execute arbitrary code or cause system instability.
The technical implementation of this vulnerability allows an authenticated attacker to leverage the HTTP server's processing of specific request parameters to trigger memory corruption. The attacker must first establish authentication credentials to access the router's administrative web interface, which provides a legitimate entry point for exploitation. Once authenticated, the attacker can craft HTTP requests containing oversized payloads that overwrite adjacent memory locations. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and can potentially lead to CWE-787, representing out-of-bounds write conditions that allow for arbitrary code execution. The exploitation process typically involves careful crafting of input data to overwrite return addresses, function pointers, or other critical memory structures that control program execution flow.
From an operational perspective, this vulnerability presents a significant risk to network security infrastructure as it enables authenticated remote code execution on affected Tenda RX9 Pro devices. The authenticated requirement reduces the attack surface compared to unauthenticated vulnerabilities, but still represents a serious concern for organizations that rely on these devices for network management. Successful exploitation could allow attackers to gain full administrative control over the router, potentially leading to complete network compromise through man-in-the-middle attacks, DNS hijacking, or the installation of persistent backdoors. The impact extends beyond individual device compromise as compromised routers can serve as stepping stones for lateral movement within networks, particularly in environments where default credentials are not changed or where multiple devices share similar configurations.
Mitigation strategies for CVE-2023-43886 should prioritize immediate firmware updates from Tenda to address the buffer overflow condition in the HTTP server component. Organizations should also implement network segmentation to limit the potential impact of compromised devices and establish monitoring for unusual HTTP traffic patterns that might indicate exploitation attempts. Network administrators should enforce strong authentication practices, including the use of complex passwords and multi-factor authentication where possible, to reduce the likelihood of unauthorized access. The vulnerability demonstrates the importance of input validation and memory safety practices in embedded systems, aligning with ATT&CK technique T1059.007 for command and scripting interpreter and T1566 for credential harvesting through network protocols. Additionally, implementing web application firewalls and intrusion detection systems can help identify and block malicious HTTP requests before they can trigger the buffer overflow condition, while regular security assessments of network infrastructure can help identify similar vulnerabilities in other network devices.