CVE-2025-5911 in EX1200T
Summary
by MITRE • 06/10/2025
A vulnerability was found in TOTOLINK EX1200T up to 4.1.2cu.5232_B20210713 and classified as critical. Affected by this issue is some unknown functionality of the file /boafrm/formDMZ of the component HTTP POST Request Handler. The manipulation leads to buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 06/16/2025
The CVE-2025-5911 vulnerability represents a critical buffer overflow flaw in TOTOLINK EX1200T routers running firmware versions up to 4.1.2cu.5232_B20210713. This vulnerability specifically targets the HTTP POST Request Handler component within the web management interface, exposing a fundamental security weakness in the device's input validation mechanisms. The affected file /boafrm/formDMZ serves as a critical entry point where malicious actors can exploit the buffer overflow condition to execute arbitrary code on the affected device. The vulnerability's classification as critical stems from its remote exploitability and the fact that a public exploit has already been disclosed, making it immediately actionable by threat actors without requiring advanced technical skills or specialized knowledge.
The technical implementation of this vulnerability occurs within the HTTP POST request handling mechanism of the router's web interface, specifically in the DMZ configuration form processing. When an attacker submits a malformed HTTP POST request to the vulnerable endpoint, the application fails to properly validate input length and content before copying data into fixed-size buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical control data structures. The vulnerability's exploitation capability extends beyond simple code execution to potentially enable full system compromise, including persistent backdoor installation, network reconnaissance, and lateral movement within the compromised network environment.
From an operational perspective, the remote exploitability of this vulnerability presents significant risk to organizations and individuals utilizing affected TOTOLINK EX1200T devices. The public disclosure of exploit code means that automated scanning tools can readily identify vulnerable devices across the internet, leading to widespread exploitation attempts. Once successfully exploited, attackers can gain full administrative control over the router, enabling them to modify network configurations, redirect traffic through malicious proxies, establish persistent access points, and potentially use the compromised device as a launchpad for attacks against other networked systems. The DMZ configuration functionality is particularly concerning since it allows attackers to modify how the router handles incoming network traffic, potentially exposing internal network resources to external threats.
Security professionals should immediately prioritize patching affected devices with firmware updates from TOTOLINK, as the vulnerability's public exploit availability makes it highly likely to be actively targeted by cybercriminals. The vulnerability aligns with CWE-121, which describes buffer overflow conditions in stack-based buffers, and may also relate to CWE-787, describing out-of-bounds writes in heap-based buffers. From an ATT&CK framework perspective, this vulnerability maps to techniques involving exploitation of remote services and privilege escalation, potentially enabling T1021.001 (Remote Services) and T1059.001 (Command and Scripting Interpreter) tactics. Organizations should implement network segmentation to isolate affected devices, monitor for suspicious network traffic patterns, and consider implementing intrusion detection systems to identify exploitation attempts. The public disclosure status of the exploit necessitates immediate action, as the window for defensive preparation is rapidly closing and organizations face increasing risk of compromise from automated attack campaigns targeting this specific vulnerability.