CVE-2025-26238 in DI-8100
Summary
by MITRE • 08/24/2026
In D-Link DI-8100G 17.12.20A1, the flag parameter in msp_info can be exploited to execute arbitrary code.
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Analysis
by VulDB Data Team • 08/24/2026
The vulnerability identified in D-Link DI-8100G firmware version 17.12.20A1 centers on a critical flaw within the management service processing logic, specifically involving the handling of the flag parameter associated with msp_info structures. This component is typically responsible for managing multi-service platform information or similar administrative data exchanges between the device’s web interface and its underlying system services. The core technical issue stems from insufficient validation and sanitization of user-supplied input when it interacts with this specific parameter. By manipulating the flag value, an attacker can bypass expected constraints, leading to a scenario where arbitrary code execution becomes possible on the affected router. This type of flaw is characteristic of improper input handling vulnerabilities that allow attackers to inject malicious payloads into system processes or scripts that are executed with elevated privileges inherent to embedded network devices.
From a technical perspective, this vulnerability aligns closely with CWE-94 Improper Control of Generation of Code (Code Injection) and potentially CWE-20 Improper Input Validation if the root cause lies in failing to restrict input characters or lengths before processing. The exploitation mechanism likely involves crafting a specially formatted request that exploits how the msp_info handler parses the flag field. If the application fails to properly escape special characters or validate the expected data types, an attacker can inject shell commands or other executable code fragments. Given that network management interfaces often run with high-level system permissions to facilitate configuration changes and diagnostics, successful exploitation grants the adversary a foothold within the device’s operating environment. This is particularly dangerous in embedded systems where security boundaries are less robust than those found in general-purpose computing environments.
The operational impact of this vulnerability is severe due to the nature of network infrastructure devices like routers. An attacker who successfully exploits this code execution flaw can gain complete control over the D-Link DI-8100G device. This level of access allows for a wide range of malicious activities, including but not limited to redirecting traffic through man-in-the-middle attacks, intercepting sensitive data such as credentials and financial information, installing persistent backdoors for long-term espionage or botnet recruitment, and using the compromised router as a pivot point to attack other devices on the internal network. Furthermore, because routers are often positioned at the perimeter of private networks, compromising one device can expose an entire local area network to external threats. The ability to execute arbitrary code effectively neutralizes any security controls implemented by the manufacturer or administrator that rely on the integrity of the underlying firmware execution environment.
In terms of threat modeling and adversary behavior, this vulnerability maps directly to MITRE ATT&CK techniques related to Initial Access and Execution. Specifically, it resembles T1190 Exploit Public-Facing Application, where attackers leverage vulnerabilities in services exposed to untrusted networks to gain initial entry. If the management interface is accessible from the internet without adequate authentication or if credentials are weak, this vulnerability can be exploited remotely over the network. Even if access requires local network proximity, the ease of code execution makes it a high-value target for automated scanning tools and opportunistic attacks targeting known vulnerable firmware versions. The persistence gained through such exploitation allows attackers to maintain long-term presence within the victim’s infrastructure, facilitating further lateral movement or data exfiltration phases in an attack chain.
Mitigation strategies must prioritize immediate patching if available from D-Link, as this represents a fundamental flaw in the application logic that cannot be easily mitigated by configuration changes alone. Administrators should ensure they are running firmware versions where this specific input validation issue has been addressed through code remediation and rigorous testing of management interface inputs. In cases where updating is not immediately feasible, network segmentation becomes critical; placing managed devices behind strict firewall rules that limit access to the management interfaces only from trusted IP addresses can reduce the attack surface significantly. Additionally, disabling remote management features if they are not strictly necessary eliminates the vector for remote exploitation entirely. Regular vulnerability assessments and monitoring of device logs for anomalous activity related to configuration changes or unexpected process executions can also aid in early detection of attempted exploits.