CVE-2025-6900 is a vulnerability identified in version 1.0 of the code-projects Library System, specifically within the /add-book.php file. The vulnerability arises from improper handling of the 'image' argument, which allows an attacker to perform an unrestricted file upload. This means that an attacker can remotely upload arbitrary files to the server without authentication or user interaction. The vulnerability is classified as medium severity with a CVSS 4.0 base score of 5.3, reflecting a network attack vector with low complexity and no required privileges or user interaction. The impact on confidentiality, integrity, and availability is low individually but combined can lead to significant consequences if exploited. Unrestricted file upload vulnerabilities often enable attackers to upload malicious scripts or web shells, potentially leading to remote code execution, server compromise, data theft, or disruption of services. Although no known exploits are currently observed in the wild, the public disclosure of the exploit code increases the risk of exploitation. The lack of available patches or mitigation from the vendor further exacerbates the threat. The vulnerability affects only version 1.0 of the Library System, which may be used by smaller or legacy library management deployments. The unrestricted upload vector is a common and critical security flaw that requires immediate attention to prevent exploitation.

For European organizations using the affected Library System 1.0, this vulnerability poses a tangible risk of server compromise through remote code execution or unauthorized file uploads. Libraries and educational institutions relying on this system could face data breaches, defacement of web portals, or service outages. The impact on confidentiality includes potential exposure of patron data or internal records. Integrity could be compromised by unauthorized modification or insertion of malicious content. Availability might be affected if attackers deploy ransomware or disrupt services via malicious uploads. Given the medium severity and lack of authentication requirements, attackers can exploit this vulnerability remotely and anonymously, increasing the risk profile. Organizations with limited IT security resources or those running legacy systems without timely patching are particularly vulnerable. The absence of known exploits in the wild currently reduces immediate risk but the public disclosure means attackers may develop exploits rapidly. European organizations should prioritize assessing their exposure, especially if they operate public-facing library management systems or similar web applications.

1. Immediate mitigation should include disabling or restricting file upload functionality in /add-book.php until a vendor patch or official fix is available. 2. Implement strict server-side validation and sanitization of uploaded files, including checking MIME types, file extensions, and scanning for malware. 3. Employ web application firewalls (WAFs) with rules to detect and block suspicious upload attempts targeting the vulnerable endpoint. 4. Restrict permissions on upload directories to prevent execution of uploaded files, e.g., by disabling execution rights on the upload folder. 5. Monitor logs for unusual upload activity or access patterns to /add-book.php. 6. If possible, isolate the affected application in a segmented network zone to limit lateral movement in case of compromise. 7. Plan for an upgrade or migration to a patched or alternative library management system version as soon as it becomes available. 8. Conduct regular security assessments and penetration testing focused on file upload mechanisms. These steps go beyond generic advice by focusing on immediate containment, layered defenses, and proactive monitoring tailored to this specific vulnerability and product.