CVE-2023-40798 in AC23
Summary
by MITRE • 08/25/2023
In Tenda AC23 v16.03.07.45_cn, the formSetIPv6status and formGetWanParameter functions do not authenticate user input parameters, resulting in a post-authentication stack overflow vulnerability.
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Analysis
by VulDB Data Team • 01/29/2026
The vulnerability identified as CVE-2023-40798 affects the Tenda AC23 router firmware version 16.03.07.45_cn, representing a critical security flaw that stems from inadequate input validation within two specific functions: formSetIPv6status and formGetWanParameter. This issue resides within the router's web interface management system, where user-supplied parameters are processed without proper authentication mechanisms, creating an exploitable condition that can be leveraged by attackers to execute arbitrary code on the affected device. The vulnerability specifically manifests as a stack overflow condition that occurs when malicious input is passed through these functions, potentially allowing remote code execution with elevated privileges. The affected firmware version demonstrates a failure in implementing proper parameter validation and input sanitization, which are fundamental security controls that should prevent buffer overflows and related memory corruption vulnerabilities.
The technical implementation of this vulnerability involves the exploitation of insufficient authentication checks within the router's web management interface. When an attacker submits crafted input parameters to the formSetIPv6status or formGetWanParameter functions, the system fails to validate the length or content of these inputs before processing them. This lack of input validation creates a classic stack buffer overflow scenario where malicious data can overwrite adjacent memory locations, potentially including return addresses and function pointers. The vulnerability's classification aligns with CWE-121 Stack-based Buffer Overflow, which occurs when a program writes data to a stack buffer without proper bounds checking, allowing the attacker to overwrite the buffer's bounds and potentially execute arbitrary code. The absence of authentication mechanisms for these functions indicates a fundamental flaw in the application's security architecture where even authenticated users could potentially exploit these vulnerabilities, though the post-authentication nature suggests that exploitation may require existing access credentials.
The operational impact of this vulnerability extends beyond simple code execution, as it can potentially allow attackers to gain full administrative control over the affected router. This compromised device could then serve as a foothold for broader network infiltration, enabling attackers to monitor network traffic, redirect DNS requests, or establish persistent backdoors within the local network. The stack overflow condition could also cause the router to crash or reboot unexpectedly, creating a denial of service condition that affects network connectivity for legitimate users. From an attacker's perspective, this vulnerability provides a pathway to escalate privileges within the router's operating system, potentially accessing sensitive configuration data, user credentials, or other confidential information stored on the device. The post-authentication nature of the vulnerability suggests that attackers would need to first obtain valid user credentials, but once obtained, they could leverage this flaw to achieve more significant compromise than what would otherwise be possible with standard authenticated access.
Mitigation strategies for CVE-2023-40798 should focus on immediate firmware updates from Tenda, as this represents a vendor-specific vulnerability requiring official patches to address the underlying authentication and input validation flaws. Network administrators should implement network segmentation and access controls to limit exposure of affected devices, while also monitoring for unusual network behavior that might indicate exploitation attempts. The implementation of web application firewalls and intrusion detection systems can help identify and block malicious input patterns targeting these specific functions. Security monitoring should include checking for unauthorized access attempts to the router's web interface, particularly around the IPv6 and WAN parameter configuration areas. Additionally, organizations should enforce strong authentication practices, including multi-factor authentication where possible, and regularly audit router configurations to ensure that only necessary services are enabled. The vulnerability's alignment with ATT&CK technique T1059.007 Command and Scripting Interpreter: PowerShell demonstrates the potential for attackers to use the compromised router as a command execution platform, making proper network monitoring and access control essential defensive measures. Regular security assessments and vulnerability scanning should be conducted to identify similar authentication bypass and input validation flaws in other network infrastructure components, as this represents a common pattern of security weakness in embedded network devices.