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Description

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.

PUBLISHED Reserved 2026-04-03 | Published 2026-04-03 | Updated 2026-04-08 | Assigner VulDB




MEDIUM: 6.9CVSS: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
MEDIUM: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C
MEDIUM: 5.3CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C
5.0AV:N/AC:L/Au:N/C:P/I:N/A:N/E:POC/RL:OF/RC:C

Problem types

Improper Access Controls

Incorrect Privilege Assignment

Product status

26.03
affected

26.03.1
unaffected

Timeline

2026-04-03:Advisory disclosed
2026-04-03:VulDB entry created
2026-04-03:VulDB entry last update

Credits

Ghufran Khan (VulDB User) reporter

VulDB CNA Team coordinator

References

vuldb.com/vuln/355091 (VDB-355091 | BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control) vdb-entry technical-description

vuldb.com/vuln/355091/cti (VDB-355091 | CTI Indicators (IOB, IOC, TTP, IOA)) signature permissions-required

vuldb.com/submit/781762 (Submit #781762 | BookstackApp BookStack v25.12.9 Improper Access Controls) third-party-advisory

github.com/...n/Permission Bypass in Markdown Chapter Export exploit

www.bookstackapp.com/blog/bookstack-release-v26-03-1/ related

github.com/...ommit/8a59895ba063040cc8dafd82e94024c406df3d04 patch

github.com/BookStackApp/BookStack/releases/tag/v26.03.1 patch

github.com/BookStackApp/BookStack/ product

cve.org (CVE-2026-5484)

nvd.nist.gov (CVE-2026-5484)

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