Privilege escalation in Bookstack
CVE-2026-86285
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.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
Affected products
- N/a Bookstack — versions 26.05.0, 26.05.1, 26.05.2
Weakness classification (CWE)
References
- cna@vuldb.com (technical-description, vdb-entry)
- cna@vuldb.com (signature, permissions-required)
- cna@vuldb.com (third-party-advisory)
- cna@vuldb.com (third-party-advisory)
- cna@vuldb.com (exploit)
- cna@vuldb.com (patch)
Frequently asked questions
- What is CVE-2026-86285?
- CVE-2026-86285 is a medium-severity vulnerability in Bookstack, classified under Incorrect Privilege Assignment. CVSS score: 4.3/10. Published 2026-09-07.
- How severe is CVE-2026-86285?
- Medium severity. CVSS v3 base score is 4.3 out of 10.