CVE-2026-50767
Summary
by MITRE • 06/27/2026
A stored cross-site scripting (XSS) vulnerability in the item 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 item type check-in message field (checkinmsg)
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Analysis
by VulDB Data Team • 06/27/2026
The vulnerability under examination represents a stored cross-site scripting flaw within the Koha Library Management System version 25.11 and earlier, specifically affecting the item type administration page. This security weakness resides in the checkinmsg field of the item type management interface, which permits authenticated administrators to inject malicious scripts that persist in the system. The vulnerability is classified as a stored XSS attack because the injected code is permanently stored within the application's database and subsequently executed whenever users access the affected page or view the stored content. This particular flaw requires an attacker to possess valid administrator credentials, but once achieved, it enables the execution of arbitrary web scripts against other users who interact with the compromised system.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the checkinmsg field handling mechanism. When administrators enter content into this field, the system fails to properly sanitize or escape the input before storing it in the database. This absence of proper security controls allows malicious payloads to be stored alongside legitimate data, creating a persistent threat vector that can affect any user who accesses the item type administration page or views records containing the compromised checkinmsg values. The vulnerability specifically targets the server-side processing of user inputs without adequate protection measures against script injection attacks, making it a classic example of improper input handling that violates fundamental security principles.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with potential access to sensitive system information and user data through various attack vectors. An authenticated attacker with administrative privileges could inject malicious scripts that steal session cookies, redirect users to phishing sites, or manipulate the application interface to perform unauthorized actions. The stored nature of the vulnerability means that any legitimate administrator who views the affected page could become compromised, potentially leading to complete system takeover or data exfiltration. This threat is particularly concerning in library environments where sensitive patron information is stored and accessed through these systems.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding mechanisms throughout the Koha application stack. The primary defense involves sanitizing all user inputs, particularly those that are stored in the database and subsequently rendered to other users. This approach aligns with CWE-79 which addresses cross-site scripting vulnerabilities through proper input validation and output encoding practices. Additionally, implementing Content Security Policy headers can provide an additional layer of protection by restricting script execution within the application context. Regular security updates and patch management procedures should be enforced to ensure that known vulnerabilities are addressed promptly, while also implementing principle of least privilege controls to limit administrative access to only necessary personnel. The ATT&CK framework categorizes this vulnerability under T1566 for credential access through exploitation of web application vulnerabilities, emphasizing the need for comprehensive web application security measures and regular penetration testing to identify similar persistent threats within library management systems.
This vulnerability demonstrates the critical importance of secure coding practices in web applications, particularly those handling sensitive information. Organizations using Koha or similar library management systems must prioritize security updates and implement proper input validation mechanisms to prevent similar stored XSS attacks from compromising their systems. The persistence of such vulnerabilities underscores the need for ongoing security awareness training and regular code reviews to identify potential injection points that could be exploited by malicious actors.