CVE-2025-34096 is a critical stack-based buffer overflow vulnerability identified in version 7.2 of Easy File Sharing HTTP Server, a product developed by EFS Software Inc. The vulnerability arises due to improper validation of the length of the 'Email' parameter in a POST request sent to the /sendemail.ghp endpoint. Specifically, the application fails to restrict the size of this input field, allowing an attacker to send an overly long string that overflows the allocated memory buffer on the stack. This memory corruption can be exploited by an unauthenticated remote attacker to execute arbitrary code with the same privileges as the server process. The vulnerability is classified under CWE-119, which relates to improper restriction of operations within the bounds of a memory buffer, a common cause of buffer overflow issues. The CVSS v4.0 base score is 9.3, indicating a critical severity level, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). No patches or known exploits in the wild have been reported at the time of publication. The flaw allows complete compromise of the affected server, potentially enabling attackers to deploy malware, pivot within networks, or exfiltrate sensitive data. Given the nature of the vulnerability, exploitation is straightforward and does not require authentication or user interaction, increasing the risk of widespread attacks if vulnerable servers are exposed to the internet.

For European organizations, this vulnerability poses a significant risk, especially for those using Easy File Sharing HTTP Server version 7.2 in their infrastructure. Successful exploitation can lead to full system compromise, resulting in unauthorized access to sensitive files, disruption of file sharing services, and potential lateral movement within corporate networks. This can cause data breaches, loss of intellectual property, and operational downtime. Given the criticality and ease of exploitation, attackers could leverage this vulnerability to deploy ransomware or other malicious payloads, severely impacting business continuity and compliance with data protection regulations such as GDPR. Organizations in sectors with high data sensitivity, including finance, healthcare, and government, are particularly vulnerable. Additionally, the lack of authentication requirement means that any exposed instance of the vulnerable server on the internet is at immediate risk, increasing the threat landscape for European enterprises relying on this software for file sharing and collaboration.

Immediate mitigation steps include identifying and isolating all instances of Easy File Sharing HTTP Server version 7.2 within the network. Since no official patch is currently available, organizations should consider temporarily disabling or restricting access to the /sendemail.ghp endpoint via web application firewalls (WAFs) or network-level filtering to block malicious POST requests with suspiciously long 'Email' parameters. Implement strict input validation and length checks at the perimeter if possible. Network segmentation should be enforced to limit the exposure of vulnerable servers to untrusted networks, especially the internet. Monitoring and logging of HTTP POST requests targeting the /sendemail.ghp endpoint should be enhanced to detect potential exploitation attempts. Organizations should also prepare for rapid patch deployment once an official fix is released by the vendor. As a longer-term strategy, consider migrating to alternative, actively maintained file sharing solutions with robust security postures. Regular vulnerability scanning and penetration testing should be conducted to detect similar buffer overflow vulnerabilities and ensure no other instances of this software version remain in use.