A vulnerability categorized as problematic has been discovered 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.
This vulnerability is registered as CVE-2026-5484. It is possible to launch the attack remotely. Furthermore, an exploit is available.
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.
