VDB-355091 · Submit #781762 · CVE-2026-5484

BookStackApp BookStack up to 26.03 Chapter Export ExportFormatter.php chapterToMarkdown pages access control

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.8	$0-$5k	0.00

Summaryinfo

A vulnerability identified as problematic has been detected in BookStackApp BookStack up to 26.03. Affected by this vulnerability is the function chapterToMarkdown of the file app/Exports/ExportFormatter.php of the component Chapter Export Handler. The manipulation of the argument pages leads to access control. This vulnerability is documented as CVE-2026-5484. The attack can be initiated remotely. Additionally, an exploit exists. You should 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.

Detailsinfo

A vulnerability was found in BookStackApp BookStack up to 26.03 and classified as problematic. This issue affects the function chapterToMarkdown of the file app/Exports/ExportFormatter.php of the component Chapter Export Handler. The manipulation of the argument pages with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Impacted is confidentiality.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-5484. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details as well as a public exploit are known. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

The exploit is available at github.com. It is declared as proof-of-concept. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product. By approaching the search of inurl:app/Exports/ExportFormatter.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 26.03.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 8a59895ba063040cc8dafd82e94024c406df3d04 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-18819). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

BookStackApp

Name

BookStack

Version

26.03

License

open-source

Website

Product: https://github.com/BookStackApp/BookStack/

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 4.8

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒
Google Hack: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: BookStack 26.03.1
Patch: 8a59895ba063040cc8dafd82e94024c406df3d04

Timelineinfo

04/03/2026 Advisory disclosed
04/03/2026 +0 days VulDB entry created
04/03/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed
Confirmation: 🔒

CVE: CVE-2026-5484 (🔒)
GCVE (CVE): GCVE-0-2026-5484
GCVE (VulDB): GCVE-100-355091
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 04/03/2026 15:16
Updated: 04/03/2026 23:10
Changes: 04/03/2026 15:16 (64), 04/03/2026 23:10 (1)
Complete: 🔍
Submitter: Ghufran Khan
Cache ID: 216::103

Submitinfo

Accepted

Submit #781762: BookstackApp BookStack v25.12.9 Improper Access Controls (by Ghufran Khan)

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.