Vulnerability · Published Oct 24, 2026 · Assigned by VulnCheck
CVE-2026-116020BookStack before 26.09.2 Incorrect Authorization via AttachmentController on Draft Pages
Medium 5.4
In plain English
A medium-severity incorrect authorization in BookStack from BookStackApp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities).
Severity (CVSS 3.1)5.4Medium
Exploit odds (30 days)0.2%top 92.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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permissions can enumerate sequential attachment IDs to download, rename, relink, or replace files on another user's unpublished draft pages.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| BookStackApp | BookStack | 0 – before 26.09.2 |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
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
- VulnCheck Advisory: BookStack before 26.09.2 Incorrect Authorization via AttachmentController on Draft Pages third-party-advisory