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.
References8
- github.com/BookStackApp/BookStack/
- github.com/BookStackApp/BookStack/commit/8a59895ba063040cc8dafd…
- github.com/BookStackApp/BookStack/releases/tag/v26.03.1
- github.com/Ghufran2/CVE-Bookstack/blob/main/Permission%20Bypass…
- vuldb.com/submit/781762
- vuldb.com/vuln/355091
- vuldb.com/vuln/355091/cti
- www.bookstackapp.com/blog/bookstack-release-v26-03-1/
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - CVSS 4.0
-
5.5
MEDIUM
Score source: CNA
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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 27 · as of 12 November 2026
- CWE
- CWE-266CWE-284
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.