CVE-2026-126811
BookStack before 26.09.3 Incorrect Authorization via Image and Drawio Endpoints
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before 26.09.3 contains an incorrect authorization vulnerability that allows authenticated users to access other users' unpublished draft page images by checking only PageView permission without draft status.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data via the base64 endpoint or rename, replace, or delete draft images by sequential ID to disclose or tamper with unpublished work.
INFO
Published Date :
Nov. 11, 2026, 8:53 p.m.
Last Modified :
Nov. 11, 2026, 8:53 p.m.
Remotely Exploit :
Yes !
Source :
VulnCheck
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 |
Solution
- Update BookStack to the latest version.
- Apply the security patch for version 26.09.3.
- Verify permission checks for draft images.
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