Medium severity · published Oct 24, 2026
CVE-2026-116020
BookStack before 26.09.2 Incorrect Authorization via AttachmentController on Draft Pages
New
5.4
CVSS
0.2%
EPSS
No
On KEV
Description
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permissions can enumerate sequential attachment IDs to download, rename, relink, or replace files on another user's unpublished draft pages.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 vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 8% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BO
BookStack · BookStackApp
before 26.09.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-116020
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-116020
codeberg.org
https://codeberg.org/bookstack/bookstack/commit/fcadecccda706b4ecaf9ac3f8e27defe0ebe78ae
codeberg.org
https://codeberg.org/bookstack/bookstack/releases/tag/v26.09.2
codeberg.org
https://codeberg.org/bookstack/bookstack/src/tag/v26.09.1/app/Uploads/Controllers/AttachmentController.php
www.bookstackapp.com
https://www.bookstackapp.com/blog/bookstack-release-v26-09-2/
www.vulncheck.com
https://www.vulncheck.com/advisories/bookstack-before-26.09.2-incorrect-authorization-via-attachmentcontroller-on-draft-pages
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