CVE-2025-10116 is a vulnerability identified in SiempreCMS versions up to 1.3.6, specifically within the /docs/admin/file_upload.php script. The vulnerability allows an attacker to perform unrestricted file uploads remotely without any authentication or user interaction. This means that an attacker can upload arbitrary files, including potentially malicious scripts, to the server hosting SiempreCMS. The vulnerability arises due to insufficient validation or restrictions on the types and contents of files accepted by the upload functionality. Exploiting this flaw could enable attackers to execute arbitrary code, escalate privileges, deface websites, or establish persistent backdoors. The CVSS 4.0 base score of 6.9 (medium severity) reflects the network attack vector, no required privileges or user interaction, and low impact on confidentiality, integrity, and availability individually but combined impact is notable. The exploit code is publicly available, increasing the risk of exploitation, although no active exploitation in the wild has been reported yet. SiempreCMS is a content management system used for website management, and this vulnerability affects all versions from 1.3.0 through 1.3.6. The lack of patches or official mitigation links in the provided data suggests that organizations using these versions remain exposed unless they implement their own controls or upgrade once a fix is released.

For European organizations using SiempreCMS, this vulnerability poses a significant risk. Successful exploitation could lead to unauthorized code execution on web servers, resulting in data breaches, website defacement, or use of compromised servers as pivot points for further network intrusion. This can damage organizational reputation, lead to regulatory non-compliance (e.g., GDPR violations if personal data is exposed), and cause operational disruptions. Since the vulnerability requires no authentication or user interaction, any public-facing SiempreCMS installation is at risk. The medium CVSS score indicates moderate but tangible impact, especially if attackers chain this vulnerability with others to escalate privileges or move laterally. European organizations in sectors with high web presence such as e-commerce, media, and government websites are particularly vulnerable. The availability of public exploit code increases the urgency to address this issue proactively.

1. Immediate mitigation should include restricting access to the /docs/admin/file_upload.php endpoint via network controls such as IP whitelisting or web application firewalls (WAF) to block unauthorized upload attempts. 2. Implement strict input validation and file type restrictions at the application or server level to prevent execution of uploaded files. 3. Monitor web server logs for suspicious upload activity or unexpected file creations. 4. If possible, disable or remove the vulnerable file upload functionality until a patch is available. 5. Regularly update SiempreCMS to the latest version once the vendor releases a security patch addressing this vulnerability. 6. Employ runtime application self-protection (RASP) or endpoint detection and response (EDR) solutions to detect and block exploitation attempts. 7. Conduct security audits and penetration tests focusing on file upload mechanisms to identify similar weaknesses. 8. Educate administrators on the risks of unrestricted file uploads and enforce the principle of least privilege for CMS administrative access.