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permissions can enumerate sequential attachment IDs to download, rename, relink, or replace files on another user's unpublished draft pages.
References5
- codeberg.org/bookstack/bookstack/commit/fcadecccda706b4ecaf9ac3…
- codeberg.org/bookstack/bookstack/releases/tag/v26.09.2
- codeberg.org/bookstack/bookstack/src/tag/v26.09.1/app/Uploads/C…
- www.bookstackapp.com/blog/bookstack-release-v26-09-2/
- www.vulncheck.com/advisories/bookstack-before-26.09.2-incorrect…
Metrics
- CVSS 3.1
-
5.4
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - CVSS 4.0
-
5.3
MEDIUM
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 8 · as of 8 November 2026
- CWE
- CWE-863
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