Medium 5.4Published Oct 24, 2026

CVE-2026-116020BookStack before 26.09.2 Incorrect Authorization via AttachmentController on Draft Pages

Updated under an hour ago (Oct 28, 2026, 5:00 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for BookStackApp BookStack

Exploited in the last 30 days

BookStack before 26.09.2 contains an incorrect authorization vulnerability in AttachmentController that allows authenticated users to access other users' draft page attachments by ID. Attackers with attachment permissions can enumerate sequential attachment IDs to download, rename, relink, or replace files on another user's unpublished draft pages.

CVSS: 5.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Weakness (CWE): CWE-863
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Awaiting Analysis
Record last updated: Oct 24, 2026
First seen by InfoSec Signals: Oct 24, 2026

Affected products

Affected products

BookStackApp BookStack bookstackapp:bookstack (from the name)	before 26.09.2	CNA record

References

References

https://codeberg.org/bookstack/bookstack/commit/fcadecccda706b4ecaf9ac3f8e27defe0ebe78ae	patch
https://www.bookstackapp.com/blog/bookstack-release-v26-09-2/	vendor-advisory, release-notes
https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.2	release-notes
https://codeberg.org/bookstack/bookstack/src/tag/v26.09.1/app/Uploads/Controllers/AttachmentController.php	technical-description
https://www.vulncheck.com/advisories/bookstack-before-26.09.2-incorrect-authorization-via-attachmentcontroller-on-draft-pages	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.