CVE-2026-4042 in i12
Summary
by MITRE • 03/12/2026
A weakness has been identified in Tenda i12 1.0.0.6(2204). The affected element is the function formWifiMacFilterGet of the file /goform/WifiMacFilterGet. This manipulation of the argument index causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been made available to the public and could be used for attacks.
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Analysis
by VulDB Data Team • 03/17/2026
The vulnerability CVE-2026-4042 represents a critical stack-based buffer overflow in the Tenda i12 router firmware version 1.0.0.6(2204) specifically within the formWifiMacFilterGet function located in the /goform/WifiMacFilterGet file. This weakness arises from improper input validation when processing the index argument parameter, creating an exploitable condition that allows attackers to manipulate memory layout through carefully crafted inputs. The vulnerability exists at the application layer within the web-based management interface of the router, making it particularly dangerous as it can be triggered through standard web browser interactions without requiring physical access to the device.
The technical implementation of this buffer overflow stems from the function's failure to properly validate the length of the index argument before copying it into a fixed-size stack buffer. According to CWE-121, this represents a classic stack-based buffer overflow vulnerability where insufficient bounds checking allows an attacker to overwrite adjacent stack memory locations. The attack vector is classified as remote since the vulnerable function is exposed through the web interface at the /goform/WifiMacFilterGet endpoint, making it accessible over the network without authentication requirements. This remote exploit capability aligns with ATT&CK technique T1190 which describes the use of remote access tools and vulnerabilities to gain unauthorized access to systems.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as demonstrated by the public availability of exploit code. An attacker could potentially execute arbitrary code on the affected device, leading to complete compromise of the router's operational environment. The compromised router could then serve as a pivot point for attacking internal network resources, enabling man-in-the-middle attacks, DNS hijacking, or serving as a command and control node for botnet activities. The vulnerability affects not only the router's web interface but also its underlying operating system, potentially allowing attackers to modify network configurations, access sensitive data, or establish persistent backdoors.
Mitigation strategies should prioritize immediate firmware updates from Tenda to address the root cause of the buffer overflow vulnerability. Network administrators should implement network segmentation to limit the attack surface and monitor for suspicious traffic patterns originating from the affected device. The use of intrusion detection systems and web application firewalls can help detect and block exploitation attempts targeting the vulnerable endpoint. Additionally, implementing strict access controls and disabling unnecessary web interfaces can reduce the attack surface. Security teams should also consider performing network scans to identify other potentially vulnerable devices within their infrastructure and establish monitoring procedures to detect unauthorized access attempts to router management interfaces. The vulnerability demonstrates the importance of proper input validation and memory management practices in embedded systems, as outlined in industry standards for secure coding practices and vulnerability remediation.