CVE-2026-5484
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk24th percentile - higher than 24% of all known CVEs
Summary
A weakness has been identified in BookStackApp BookStack up to version 26.03 in the chapterToMarkdown function of app/Exports/ExportFormatter.php (Chapter Export Handler). Manipulating the pages argument can lead to improper access controls. The attack can be launched remotely and the exploit is publicly available.
Risk Assessment
The organization is at risk of unauthorized access to exported chapters, potentially leading to data leakage or content integrity compromise.
Recommendation
Upgrade BookStack to version 26.03.1 immediately, which includes patch 8a59895ba063040cc8dafd82e94024c406df3d04 fixing the vulnerability.
Original NVD description (English source)
A weakness has been identified in BookStackApp BookStack up to 26.03. Affected is the function chapterToMarkdown of the file app/Exports/ExportFormatter.php of the component Chapter Export Handler. Executing a manipulation of the argument pages can lead to improper access controls. It is possible to launch the attack remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 26.03.1 is able to address this issue. This patch is called 8a59895ba063040cc8dafd82e94024c406df3d04. It is advisable to upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.