CVE-2026-50765 in Library Management System
Summary
by MITRE • 06/27/2026
Cross-Site Scripting (XSS) vulnerability in the patron restriction type administration page of Koha Library Management System through 25.11 allows an authenticated remote attacker with administrator privileges to inject arbitrary web scripts via the restriction type label (display_text field)
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Analysis
by VulDB Data Team • 06/27/2026
This cross-site scripting vulnerability exists within the Koha Library Management System version 25.11 and earlier, specifically affecting the patron restriction type administration page. The flaw stems from insufficient input validation and output encoding of user-supplied data within the display_text field of restriction type labels. An authenticated attacker possessing administrator privileges can exploit this weakness by injecting malicious JavaScript code into the display_text parameter during the creation or modification of patron restriction types. The vulnerability represents a classic reflected XSS attack vector where malicious scripts execute in the context of other users' browsers when they view the affected administrative page. This occurs because the system fails to properly sanitize and encode user input before rendering it back to the browser interface, allowing attacker-controlled content to be interpreted as executable script rather than static text.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with a persistent means of compromising the library management system's administrative environment. Once exploited, the malicious scripts can perform actions such as stealing session cookies, redirecting users to phishing sites, modifying patron records, or even executing unauthorized administrative commands through the compromised administrator account. The vulnerability is particularly concerning in library environments where sensitive patron data is stored and managed, as successful exploitation could lead to data breaches, privacy violations, and potential system compromise. Attackers could leverage this weakness to maintain persistent access to the system while remaining undetected, making it a significant threat to information security.
This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and corresponds to ATT&CK technique T1059.007 for script injection attacks targeting web interfaces. The exploitation requires an attacker to already possess administrative credentials, but this does not mitigate the severity as it still enables privilege escalation within the application's administrative domain. Organizations using Koha systems should prioritize immediate patching to address this vulnerability and implement proper input validation mechanisms throughout the application's data handling processes. The mitigation strategy involves implementing strict output encoding for all user-supplied content, particularly in administrative interfaces where privileged actions can be performed, and ensuring that all HTML content is properly escaped before being rendered in web pages to prevent script execution.
Additional defensive measures include implementing Content Security Policy headers to limit script execution sources, establishing regular security code reviews focusing on input validation practices, and conducting comprehensive penetration testing of administrative interfaces. Organizations should also consider implementing multi-factor authentication for administrator accounts and monitoring access logs for suspicious activities that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of validating and sanitizing all user inputs in web applications, particularly within privileged administrative sections where the potential impact of successful attacks is greatest. Regular security assessments and timely patch management remain essential practices to protect against such vulnerabilities in library management systems handling sensitive patron information.