CVE-2025-67433 identifies a heap buffer overflow vulnerability in the processRequest function of Open TFTP Server MultiThreaded version 1.7. The vulnerability arises when the server processes a crafted DATA packet that exceeds expected buffer boundaries, leading to memory corruption. This memory corruption can cause the server process to crash, resulting in a Denial of Service (DoS) condition. The TFTP protocol is commonly used for simple file transfers, often in embedded systems, network devices, and legacy infrastructure. Since TFTP typically operates without authentication and on UDP port 69, an attacker with network access can exploit this vulnerability remotely without user interaction. No CVSS score has been assigned yet, and no patches or mitigations have been officially released. The vulnerability is currently not known to be exploited in the wild. However, the impact on availability is significant as it can disrupt critical file transfer operations. The lack of authentication and the ease of triggering the overflow make this a high-risk vulnerability for affected systems. Organizations relying on Open TFTP Server MultiThreaded v1.7 should prioritize monitoring and network segmentation to reduce exposure until a patch is available.

The primary impact of CVE-2025-67433 is a Denial of Service condition caused by a heap buffer overflow crash in the TFTP server. For European organizations, this can disrupt automated file transfer processes critical in network device provisioning, firmware updates, and embedded system management. Sectors such as manufacturing, telecommunications, and critical infrastructure that use TFTP for device configuration could experience operational downtime. The vulnerability could also be leveraged as part of a larger attack chain to degrade network reliability or delay incident response. Although no data confidentiality or integrity compromise is indicated, the loss of availability can have cascading effects on business continuity and service delivery. The ease of exploitation without authentication increases the risk, especially in environments where TFTP servers are exposed to untrusted networks or insufficiently segmented internal networks.

1. Immediately restrict network access to the Open TFTP Server MultiThreaded service by implementing firewall rules that limit UDP port 69 traffic to trusted hosts only. 2. Employ network segmentation to isolate TFTP servers from general user networks and the internet. 3. Monitor network traffic for unusual or malformed TFTP DATA packets that could indicate exploitation attempts. 4. Disable the TFTP service on systems where it is not strictly necessary. 5. Maintain an inventory of devices and systems running Open TFTP Server MultiThreaded v1.7 to prioritize remediation. 6. Engage with the software vendor or community to obtain patches or updates as soon as they become available. 7. Consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures tailored to detect malformed TFTP packets. 8. Implement robust logging and alerting on TFTP server crashes to enable rapid incident response. 9. For embedded or legacy devices that cannot be patched, evaluate alternative secure file transfer methods or additional compensating controls.