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Medium · 5.4 CVE-2026-126811 EUVD-2026-124026GHSA-gx3w-9hmm-83wm

BookStack before 26.09.3 Incorrect Authorization via Image and Drawio Endpoints

Published Nov 11, 2026 · Updated Nov 12, 2026 · Assigned by VulnCheck

Description

BookStack before 26.09.3 contains an incorrect authorization vulnerability that allows authenticated users to access other users' unpublished draft page images by checking only PageView permission without draft status. Attackers can read drawio data via the base64 endpoint or rename, replace, or delete draft images by sequential ID to disclose or tamper with unpublished work.

Affected products

VendorProductAffectedFixed
BookStackApp BookStack < 26.09.3 26.09.3

References