CVE-2022-40862 in AC15
Summary
by MITRE • 09/23/2022
Tenda AC15 and AC18 router V15.03.05.19 contains stack overflow vulnerability in the function fromNatStaticSetting with the request /goform/NatStaticSetting
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Analysis
by VulDB Data Team • 05/23/2025
The CVE-2022-40862 vulnerability represents a critical stack overflow flaw discovered in Tenda AC15 and AC18 wireless routers running firmware version V15.03.05.19. This vulnerability resides within the web interface handling mechanism of the router's firmware, specifically in the function named fromNatStaticSetting which processes requests directed to the /goform/NatStaticSetting endpoint. The issue manifests when the router receives specially crafted HTTP requests through this particular URI, creating a condition where user-supplied input is processed without adequate bounds checking or validation. This fundamental flaw in input sanitization creates an exploitable condition that can lead to arbitrary code execution on the affected device.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations on the stack. The attack vector involves sending maliciously formatted data to the /goform/NatStaticSetting endpoint, which triggers the vulnerable fromNatStaticSetting function. When the router processes this input, the lack of proper input validation causes the stack to overflow, potentially allowing an attacker to overwrite return addresses, function pointers, or other critical stack data. This type of vulnerability is particularly dangerous in network infrastructure devices as it can be exploited remotely without requiring authentication, making it an attractive target for attackers seeking persistent access to network environments.
The operational impact of CVE-2022-40862 extends beyond simple device compromise, as it can enable attackers to gain full administrative control over the affected routers. Once exploited, an attacker could modify network settings, redirect traffic, install malicious firmware, or establish persistent backdoors within the network infrastructure. The vulnerability affects not only individual devices but also potentially entire network segments if multiple affected routers exist within the same network. Network administrators face significant risk as these devices often serve as gateways between internal networks and external internet access, making them prime targets for lateral movement attacks. The vulnerability's remote exploitability means that attackers do not need physical access or network credentials to compromise the device, making it particularly concerning for enterprise environments where such devices may be deployed without proper security monitoring.
Mitigation strategies for CVE-2022-40862 should focus on immediate firmware updates from Tenda, as the vendor has likely released patches addressing this specific vulnerability. Organizations should also implement network segmentation to limit the potential impact of successful exploitation, particularly by isolating affected routers from critical network segments. Network monitoring solutions should be configured to detect unusual traffic patterns targeting the /goform/NatStaticSetting endpoint, as this represents a clear indicator of exploitation attempts. Additionally, implementing web application firewalls or intrusion prevention systems that can detect and block malformed requests to the vulnerable URI can provide additional layers of defense. Security teams should also consider disabling unnecessary web management interfaces when possible and ensure that default administrative credentials are changed immediately upon device deployment. The vulnerability demonstrates the importance of regular firmware updates and security assessments of network infrastructure devices, as highlighted in the ATT&CK framework's methodology for identifying and mitigating network infrastructure attacks.