CVE-2026-5484CWE-266CWE-284

BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control

Medium · published April 3, 2026

CVSS v4.0
6.9
EPSS
1%
Percentile
45.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P
EPSS
0.00550 · 45.2th percentile
Weaknesses
CWE-266 · Incorrect Privilege Assignment; CWE-284 · Improper Access Control
Published
2026-04-03T19:45Z
EPSS history
Timeline
  • 03 APR 19:45Z
    BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control
    cvelistv5