CVE-2025-3346 in AC7
Summary
by MITRE • 04/07/2025
A vulnerability was found in Tenda AC7 15.03.06.44. It has been rated as critical. Affected by this issue is the function formSetPPTPServer of the file /goform/SetPptpServerCfg. The manipulation of the argument pptp_server_start_ip/pptp_server_end_ip leads to buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 05/27/2025
The vulnerability identified as CVE-2025-3346 represents a critical buffer overflow condition within the Tenda AC7 router firmware version 15.03.06.44. This issue resides in the formSetPPTPServer function located within the /goform/SetPptpServerCfg file, which serves as a web interface endpoint for configuring PPTP server settings. The flaw manifests when manipulating the pptp_server_start_ip and pptp_server_end_ip parameters, which are processed without adequate input validation or boundary checking. This specific implementation violates fundamental security principles and creates an exploitable condition that can be leveraged by remote attackers to execute arbitrary code on the affected device.
The technical exploitation of this vulnerability follows a classic buffer overflow pattern where insufficient bounds checking allows an attacker to write data beyond the allocated memory buffer space. When the pptp_server_start_ip and pptp_server_end_ip parameters exceed their expected length limits, the system's memory management becomes compromised, potentially allowing attackers to overwrite adjacent memory locations including return addresses and function pointers. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write conditions. The remote attack vector means that an unauthenticated attacker can exploit this flaw from outside the network perimeter, making it particularly dangerous for network infrastructure devices.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected router. Successful exploitation could enable attackers to modify network configurations, establish persistent backdoors, redirect traffic through malicious proxies, or use the compromised device as a launching point for further attacks against internal network resources. The PPTP server configuration interface is typically accessible to legitimate users for legitimate purposes, but the lack of input sanitization creates a dangerous attack surface that could be leveraged for privilege escalation or lateral movement within network environments. This vulnerability directly aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1021.001 for remote services, as attackers could use the compromised router to establish persistent remote access or conduct network reconnaissance.
Mitigation strategies for CVE-2025-3346 must include immediate firmware updates from Tenda to address the buffer overflow condition in the affected PPTP server implementation. Network administrators should disable PPTP server functionality if it is not required for operations, as this reduces the attack surface and eliminates the exploitable code path. Additionally, implementing network segmentation and access controls can limit the potential impact of successful exploitation. The vulnerability highlights the importance of proper input validation and memory management practices in embedded systems, particularly those handling user-provided parameters in web interfaces. Organizations should also consider network monitoring to detect anomalous traffic patterns that might indicate exploitation attempts, and maintain updated vulnerability management processes to ensure timely patch deployment across all network infrastructure devices.