CVE-2024-5293 is a stack-based buffer overflow vulnerability identified in the D-Link DIR-2640-US router firmware version 1.11B02_BETA02. The vulnerability resides in the prog.cgi script, which processes Home Network Administration Protocol (HNAP) requests served by the embedded lighttpd webserver listening on TCP ports 80 and 443. The root cause is the absence of proper bounds checking on the length of user-supplied data before it is copied into a fixed-length stack buffer, leading to a classic stack buffer overflow (CWE-121). This flaw allows a remote attacker, positioned on the same network segment (network-adjacent), to send specially crafted HTTP Referer headers or HNAP requests that overflow the buffer and overwrite the stack, enabling arbitrary code execution with root privileges. No authentication or user interaction is required, which significantly lowers the barrier to exploitation. The vulnerability was assigned CVSS v3.0 base score 8.8, reflecting high impact on confidentiality, integrity, and availability. Although no known exploits are currently in the wild, the critical nature of the flaw and the ease of exploitation make this a significant threat to affected devices. The vulnerability was disclosed by the Zero Day Initiative (ZDI) under identifier ZDI-CAN-21853. No official patches or firmware updates have been published at the time of disclosure, increasing the urgency for mitigations.

The impact of CVE-2024-5293 is severe for organizations using the D-Link DIR-2640-US router, especially those running the affected firmware version 1.11B02_BETA02. Successful exploitation grants attackers root-level remote code execution capabilities, allowing full control over the device. This can lead to interception or manipulation of network traffic, deployment of persistent malware, lateral movement within internal networks, and disruption of network availability. Confidential information passing through the router could be compromised, and the integrity of network operations undermined. Since the router often serves as a gateway device, compromise can facilitate attacks against connected systems and critical infrastructure. The lack of authentication requirement and the exposure of HTTP/HTTPS management interfaces increase the risk of exploitation by both internal and external threat actors positioned on the local network or VPN. Organizations relying on this router in enterprise, SMB, or home environments face significant operational and security risks until the vulnerability is remediated.

1. Immediate mitigation should focus on network segmentation and access control: restrict access to the router's management interfaces (ports 80 and 443) to trusted IP addresses only, ideally via firewall rules or VLAN segmentation. 2. Disable remote management features if enabled, especially over WAN interfaces, to reduce exposure. 3. Monitor network traffic for unusual or malformed HNAP requests or HTTP Referer headers targeting the router. 4. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting exploitation attempts targeting this vulnerability. 5. Regularly check for and apply official firmware updates or patches from D-Link as soon as they become available. 6. If patching is delayed, consider replacing affected devices with models not vulnerable to this issue. 7. Conduct internal audits to identify all instances of the DIR-2640 router and verify firmware versions to prioritize remediation. 8. Educate network administrators about the vulnerability and the importance of limiting administrative interface exposure. These steps go beyond generic advice by focusing on network-level controls and proactive monitoring tailored to the specific vulnerability vectors.