CVE-2025-40678 is a medium-severity vulnerability classified under CWE-434, which pertains to the unrestricted upload of files with dangerous types. This vulnerability affects Summar Software's product 'Portal del Empleado', specifically version 3.98.0. The issue arises from insufficient validation or restrictions on the types of files that can be uploaded via the web application. An attacker can exploit this vulnerability by sending a crafted POST request to the endpoint '/MemberPages/ntf_absentismo.aspx', using the parameter 'cctl00$ContentPlaceHolder1$fuAdjunto' to upload a file with a potentially dangerous extension or content. Because the vulnerability allows uploading files without proper checks, it could enable attackers to upload malicious scripts, executables, or other harmful files that could be executed on the server or accessed by other users. The CVSS 4.0 vector indicates the attack is network-based (AV:N), requires low attack complexity (AC:L), no privileges (PR:L - low privileges), no user interaction (UI:N), and has limited impact on confidentiality, integrity, and availability (VC:L, VI:N, VA:L). The vulnerability does not require user interaction and can be exploited remotely, increasing its risk profile. However, the impact is somewhat limited due to the requirement of low privileges and the limited scope of the vulnerability. There are no known exploits in the wild at the time of publication, and no patches have been linked yet. The vulnerability was reserved in April 2025 and published in September 2025, indicating recent discovery and disclosure. Overall, this vulnerability represents a risk of unauthorized file uploads that could lead to server compromise, data leakage, or further exploitation if combined with other vulnerabilities or misconfigurations.

For European organizations using Summar Software's Portal del Empleado version 3.98.0, this vulnerability poses a tangible risk of unauthorized file uploads that could lead to server-side compromise or data breaches. Given that Portal del Empleado is an employee portal, it likely handles sensitive HR data, attendance records, and possibly personal employee information. Exploitation could result in unauthorized access to confidential employee data, disruption of HR operations, or the deployment of malware within the corporate network. The medium CVSS score reflects a moderate risk, but the potential impact on confidentiality and availability of sensitive employee data is significant. Additionally, if attackers manage to upload web shells or malicious scripts, they could pivot within the network, escalating the threat. European organizations are subject to strict data protection regulations such as GDPR; a breach involving employee personal data could lead to regulatory penalties and reputational damage. The lack of known exploits in the wild currently reduces immediate risk, but the vulnerability should be addressed promptly to prevent future exploitation.

1. Immediate mitigation should include implementing strict server-side validation of uploaded files, restricting allowed file types to only those necessary for business operations (e.g., PDFs, images) and blocking executable or script files. 2. Employ content inspection techniques such as MIME type verification and file signature checks rather than relying solely on file extensions. 3. Configure the web server and application to store uploaded files outside the web root or in directories that do not allow execution of uploaded content. 4. Apply access controls and sandboxing to uploaded files to prevent execution or access by unauthorized users. 5. Monitor logs for unusual upload activity or attempts to upload disallowed file types. 6. If possible, implement multi-factor authentication and least privilege principles to limit the ability of low-privilege users to upload files. 7. Engage with Summar Software for official patches or updates addressing this vulnerability and apply them as soon as they become available. 8. Conduct regular security assessments and penetration testing focusing on file upload functionalities to detect similar issues proactively.