CVE-2026-67204 — BookStack < 26.05.4 Broken Access Control via Image Gallery API
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 use…
Published: 2026-08-24 · CVSS: 5.3 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7