CVE-2026-67204
BookStack < 26.05.4 Broken Access Control via Image Gallery API
- State
- Published
- Severity
- 5.3 Medium
- Published
- Aug 24, 2026
- Updated
- Oct 1, 2026
- Reserved
- Jul 28, 2026
Description
BookStack before 26.05.4 contains a broken access control vulnerability that allows authenticated API users with image-update or image-delete permissions to manipulate other users' avatars by exploiting missing content-type restrictions in the Image Gallery API endpoints. Attackers can supply a user avatar's ID to the API controller, which loads any image type without the web controller's gallery and drawio restrictions, and when the avatar's uploaded_to field matches a page ID accessible to the attacker, the authorization check passes allowing the attacker to rename, replace, or delete the target user's avatar without requiring user-management permission.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.3 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.4 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L | VulnCheck |
Weaknesses
- CWE-863 Incorrect Authorization
Affected Products
| Product | Versions |
|---|---|
BookStackBookStackApp |
|
References
- Maintainer Blogvendor-advisory
- Codeberg Release Notesrelease-notes
- BookStack v26.05.4 Release Notesrelease-notes
- https://www.vulncheck.com/advisories/bookstack-broken-access-control-via-image-gallery-apithird-party-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.