Executive brief
Koha is an open-source system used by libraries to manage books and member records. A security flaw in the administrative interface allows a user with staff privileges to inject malicious code into the system. This code could then execute in the browsers of other library staff members, potentially leading to unauthorized actions or the theft of sensitive administrative session information.
Technical details
A stored Cross-Site Scripting (XSS) vulnerability exists in the patron restriction type administration page of Koha through version 25.11. The root cause is located in 'admin/restrictions.tt' (lines 263-267), where the 'display_text' field is rendered using the '$raw' filter inside a JavaScript object literal without proper encoding or sanitization. An authenticated attacker with administrator or 'superlibrarian' privileges can inject a payload (e.g., a script block termination sequence) into the restriction type label. When other staff members view the restriction types page, the injected script executes in their browser context. A fix involves replacing the '$raw' filter with the 'json' filter to ensure proper encoding.
Affected products
- Koha Koha Library Management System Through 25.11
Timeline
- 2026-06-26: disclosed: CVE published to NVD