CVE-2025-26872 is a critical security vulnerability classified under CWE-434, which pertains to the unrestricted upload of files with dangerous types in the dkszone Eximius product, affecting versions up to 2.2. This vulnerability allows an attacker with at least low privileges (PR:L) and no user interaction (UI:N) to upload malicious files to the system remotely (AV:N). The vulnerability is severe due to its potential to compromise confidentiality, integrity, and availability (C:H/I:H/A:H) of the affected system, with a CVSS v3.1 base score of 9.9. The scope of the vulnerability is changed (S:C), indicating that exploitation can affect resources beyond the initially vulnerable component. The core issue is that the application does not properly restrict or validate the types of files that can be uploaded, enabling attackers to upload files that could be executed or used to escalate privileges, inject malicious code, or disrupt services. Since the vulnerability requires low privileges but no user interaction, it could be exploited by authenticated users or insiders to gain further control or cause damage. The lack of available patches at the time of publication increases the risk, as organizations must rely on mitigation until a fix is released. No known exploits in the wild have been reported yet, but the critical severity and ease of exploitation make it a high-priority issue for affected users.

For European organizations, this vulnerability poses a significant risk, especially for those using the dkszone Eximius software in their infrastructure. The ability to upload malicious files unrestrictedly can lead to remote code execution, data breaches, defacement, or denial of service. Confidential information could be exfiltrated or corrupted, and system availability could be disrupted, impacting business operations and compliance with data protection regulations such as GDPR. The critical nature of the vulnerability means that attackers could leverage it to pivot within networks, potentially affecting interconnected systems and services. Organizations in sectors with high regulatory scrutiny or critical infrastructure reliance on Eximius are particularly vulnerable to reputational damage, financial loss, and legal penalties if exploited.

Immediate mitigation steps include implementing strict file upload validation controls at the application and network layers. Organizations should restrict allowed file types to only those necessary for business operations, using server-side validation rather than relying solely on client-side checks. Employing web application firewalls (WAFs) with rules to detect and block suspicious file uploads can provide an additional layer of defense. Monitoring and logging file upload activities to detect anomalies is crucial. Access controls should be reviewed and tightened to limit upload permissions to trusted users only. Until an official patch is released, consider disabling file upload functionality if feasible or isolating the affected system in a segmented network zone to reduce potential impact. Regularly check for vendor updates or patches and apply them promptly once available. Conduct security awareness training to inform users about the risks associated with file uploads and suspicious files.