CVE-2026-1134 is a cross-site scripting vulnerability identified in itsourcecode Society Management System version 1.0. The vulnerability exists in the /admin/expenses.php file, where the 'detail' parameter is improperly sanitized, allowing an attacker to inject malicious JavaScript code. This vulnerability can be exploited remotely without authentication, but requires user interaction, such as an administrator clicking a crafted link or viewing manipulated input. The vulnerability enables attackers to execute arbitrary scripts in the context of the victim's browser, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions within the application. The vulnerability has a CVSS 4.0 base score of 5.3, reflecting medium severity, with attack vector being network-based, low attack complexity, no privileges required, and user interaction needed. Although no known exploits are currently observed in the wild, a public proof-of-concept exploit exists, increasing the likelihood of exploitation attempts. The affected product is primarily used for managing societies or community organizations, which often handle sensitive financial and personal data. The lack of available patches at the time of publication necessitates immediate mitigation through input validation, output encoding, and access control measures. This vulnerability highlights the importance of secure coding practices in web applications, especially those handling administrative functions.

For European organizations using the itsourcecode Society Management System 1.0, this vulnerability poses risks to confidentiality and integrity of sensitive data, particularly financial and personal information managed within the system. Successful exploitation could allow attackers to hijack administrator sessions, execute unauthorized commands, or steal credentials, potentially leading to broader compromise of organizational resources. Given the administrative context of the vulnerable page, the impact could extend to manipulation of financial records or unauthorized expense approvals. Although availability impact is minimal, the reputational damage and regulatory consequences (e.g., GDPR violations due to data leakage) could be significant. Organizations relying on this system for community or society management may face operational disruptions and loss of trust from their members. The medium severity rating suggests a moderate but actionable threat, especially since exploitation requires only user interaction and no authentication. The public availability of exploit code increases the urgency for mitigation to prevent targeted attacks.

1. Monitor the vendor’s communications closely for official patches or updates addressing CVE-2026-1134 and apply them promptly once available. 2. Implement strict input validation on the 'detail' parameter and any other user-supplied inputs, ensuring that special characters are properly sanitized or rejected. 3. Apply context-appropriate output encoding (e.g., HTML entity encoding) to prevent injected scripts from executing in the browser. 4. Restrict access to the /admin/expenses.php page to trusted IP addresses or via VPN to reduce exposure. 5. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in the browser. 6. Educate administrators and users about the risks of clicking on suspicious links or inputs, emphasizing cautious handling of URLs and inputs related to the admin interface. 7. Conduct regular security assessments and code reviews focusing on input handling and output encoding in the application. 8. Consider deploying web application firewalls (WAFs) with rules to detect and block XSS attack patterns targeting this parameter. 9. Maintain comprehensive logging and monitoring to detect unusual activities that may indicate exploitation attempts. 10. If feasible, isolate the Society Management System from other critical infrastructure to contain potential breaches.