Is there a public PoC exploit available for CVE-2026-5484?

Yes, a public proof-of-concept exploit is available for CVE-2026-5484. Prioritise patching immediately. EPSS: 0.0%.

Is there a patch available for CVE-2026-5484?

Yes, a patch is available for CVE-2026-5484. Update the affected software to the latest version immediately.

PHP CVE-2026-5484

Q: What is the CVSS score of CVE-2026-5484?

CVE-2026-5484 has a CVSS 4.0 base score of 5.5 (Medium). CVSS 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/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 exploitation probability: 0.0%.

EUVD-2026-18819 MEDIUM

Improper Access Control (CWE-284)

2026-04-03 VulDB

GHSA-h29h-hh8g-q4wh

PHP Authentication Bypass Bookstack

5.5

CVSS 4.0 · Vendor: VulDB

Severity by source

Vendor (VulDB) PRIMARY

5.5 MEDIUM

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

Primary rating from Vendor (VulDB) · only source for this CVE.

CVSS VectorVendor: VulDB

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

PoC Detected

Apr 07, 2026 - 13:20 vuln.today

Public exploit code

EUVD ID Assigned

Apr 03, 2026 - 20:00 euvd

EUVD-2026-18819

Analysis Generated

Apr 03, 2026 - 20:00 vuln.today

Patch released

Apr 03, 2026 - 20:00 nvd

Patch available

CVE Published

Apr 03, 2026 - 19:45 nvd

MEDIUM 5.5

DescriptionCVE.org

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.

AnalysisAI

BookStack chapter export functionality allows unauthenticated remote attackers to bypass access controls via manipulation of the pages parameter in the chapterToMarkdown function, enabling improper access to restricted content. Affects BookStack versions up to 26.03; patch available in version 26.03.1. Publicly available exploit code exists and CVSS 5.5 reflects low confidentiality impact with no integrity or availability compromise.

Technical ContextAI

The vulnerability resides in BookStack's export functionality, specifically the chapterToMarkdown method within app/Exports/ExportFormatter.php. BookStack is a PHP-based documentation and wiki platform. The root cause is classified as CWE-284 (Improper Access Control), indicating insufficient validation of the pages parameter during chapter export operations. This parameter manipulation allows attackers to circumvent intended access restrictions without requiring authentication, as confirmed by the CVSS vector showing PR:N (no privileges required) and AV:N (network-accessible). The export handler fails to properly validate which pages a user is authorized to access before including them in the exported markdown output.

RemediationAI

Vendor-released patch: upgrade to BookStack version 26.03.1 or later. The specific patch commit 8a59895ba063040cc8dafd82e94024c406df3d04 is available on GitHub. Users unable to upgrade immediately should restrict network access to BookStack instances and review export functionality logs for unauthorized chapter access attempts. Official vendor advisory and release notes are available at https://www.bookstackapp.com/blog/bookstack-release-v26-03-1/ and https://github.com/BookStackApp/BookStack/releases/tag/v26.03.1.