CVE-2025-70243 in DIR-513
Summary
by MITRE • 03/09/2026
Stack buffer overflow vulnerability in D-Link DIR-513 v1.10 via the curTime parameter to goform/formSetWAN_Wizard534.
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Analysis
by VulDB Data Team • 03/12/2026
This vulnerability represents a critical stack buffer overflow in D-Link DIR-513 router firmware version 1.10 which exposes a remote code execution risk through the web management interface. The flaw occurs within the goform/formSetWAN_Wizard534 endpoint when processing the curTime parameter, allowing attackers to craft malicious requests that overwrite adjacent stack memory. The vulnerability stems from improper input validation and bounds checking within the firmware's web form processing logic, where user-supplied data is directly copied to a fixed-size stack buffer without adequate length verification. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a high-risk weakness in software security design. The attack vector is particularly concerning as it enables remote exploitation without authentication, making it accessible to any attacker who can reach the device's web interface. The operational impact extends beyond simple denial of service to potentially allow full system compromise, as the buffer overflow can be leveraged to overwrite return addresses and execute arbitrary code. This vulnerability aligns with ATT&CK technique T1210 Exploitation of Remote Services, specifically targeting network infrastructure devices that are often overlooked in security assessments. The affected device model DIR-513 running firmware version 1.10 represents a common consumer-grade router that typically operates in unsecured environments, increasing the attack surface and potential for widespread exploitation.
The technical implementation of this vulnerability demonstrates poor memory management practices within the embedded firmware codebase, where the curTime parameter is processed through a vulnerable function that does not perform adequate bounds checking before copying data to a stack buffer. The buffer overflow occurs during form processing when the device fails to validate the length of the input parameter against the allocated buffer size, creating a situation where attacker-controlled data can overwrite critical stack memory locations. This flaw is particularly dangerous because it operates within the device's legitimate administrative interface, meaning that the exploitation does not require specialized tools or physical access to the device. The vulnerability exists in the web server component of the firmware, specifically within the form handling mechanism that processes user inputs for WAN configuration wizards. The lack of input sanitization and proper buffer management creates a predictable exploitation pattern that can be automated, making this vulnerability particularly attractive to threat actors seeking to compromise home and small office networks. The attack chain typically involves sending a crafted HTTP request containing an oversized curTime parameter to the vulnerable endpoint, which then triggers the buffer overflow condition.
The implications of this vulnerability extend beyond immediate exploitation to include potential network-wide compromise and persistent backdoor access. Once successfully exploited, an attacker could gain full administrative control over the router, enabling them to modify network configurations, redirect traffic, or establish persistent access points for further attacks. The vulnerability's presence in consumer-grade networking equipment means that it affects a large number of devices that are often deployed in environments with minimal security oversight, including residential networks, small businesses, and IoT ecosystems. Network segmentation and firewall rules may not prevent exploitation since the vulnerability is accessible through the standard web management interface, which is typically exposed to local network users. The device's role as a network gateway makes it an ideal target for attackers seeking to establish persistent access points or redirect network traffic for malicious purposes. This vulnerability also demonstrates the broader issue of embedded device security, where firmware updates are often delayed or never deployed, leaving devices vulnerable to known exploits for extended periods. The lack of proper input validation in the web interface represents a fundamental flaw in the device's security architecture that could potentially allow for privilege escalation or information disclosure attacks.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from D-Link, as the manufacturer is responsible for providing security patches to address this specific buffer overflow condition. Organizations and individuals should implement network monitoring to detect exploitation attempts through unusual traffic patterns or malformed requests to the affected endpoint. Network segmentation and access control measures can help limit the impact if exploitation occurs, while regular firmware update policies should be established to ensure all network devices receive security patches in a timely manner. The vulnerability highlights the importance of input validation and proper bounds checking in embedded systems, which should be implemented according to secure coding practices and security standards such as those defined by the Open Web Application Security Project. Network administrators should also consider implementing intrusion detection systems that can identify exploitation attempts targeting known vulnerabilities in network infrastructure devices. The incident underscores the need for regular security assessments of network equipment and the importance of maintaining up-to-date security knowledge to identify and remediate similar vulnerabilities across the entire network infrastructure. Given the nature of the vulnerability, any network monitoring solution should be configured to detect abnormal parameter lengths being sent to web form endpoints, particularly those that process configuration data.