CVE-2026-86285

BookStack Attachment Edit Endpoint AttachmentController.php getUpdateForm access control

State: Published
Severity: 5.3 Medium
Published: Sep 7, 2026
Updated: Sep 9, 2026
Reserved: Sep 6, 2026

Description

A vulnerability was detected in BookStack up to 26.05.2. Affected by this issue is the function AttachmentController::getUpdateForm of the file app/Uploads/Controllers/AttachmentController.php of the component Attachment Edit Endpoint. The manipulation of the argument ID results in improper access controls. The attack may be launched remotely. The exploit is now public and may be used. The patch is identified as 4e406c41c4c8060a5795e74c66fb96362e54f400. It is advisable to implement a patch to correct this issue.

Scores

CVSS	Score	Vector	Source
4.0	5.3 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P	VulDB
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C	VulDB
3.0	4.3 Medium	CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C	VulDB
2.0	4.0 Medium	AV:N/AC:L/Au:S/C:P/I:N/A:N/E:POC/RL:OF/RC:C	VulDB

Weaknesses

CWE-284 Improper Access Controls
CWE-266 Incorrect Privilege Assignment

Affected Products

Product	Versions
BookStackn/a	26.05.0Affected 26.05.1Affected 26.05.2Affected

References

VDB-399445 | BookStack Attachment Edit Endpoint AttachmentController.php getUpdateForm access controlvdb-entrytechnical-description
VDB-399445 | CTI Indicators (IOB, IOC, TTP, IOA)signaturepermissions-required
CVE-2026-86285 | CVE Analysis and Reportthird-party-advisory
Submit #905693 | BookStack 26.05.2 Missing authorization / Broken Access Controlthird-party-advisory
https://ashutosh-jena.in/blog/broken-access-control-in-bookstack-how-a-missing-permission-check-leaked-attachment-dataexploit
https://codeberg.org/bookstack/bookstack/commit/4e406c41c4c8060a5795e74c66fb96362e54f400patch

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