{"id":"CVE-2026-67204","title":"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 …","summary":"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 …","severity":"medium","cvss":5.4,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L","cwe":["CWE-863"],"published":"2026-08-24","updated":"2026-09-24","sourceUpdated":"2026-09-24T20:43:32.537","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-67204","references":[{"url":"https://codeberg.org/bookstack/bookstack/releases/tag/v26.05.4","label":"disclosure@vulncheck.com"},{"url":"https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4","label":"disclosure@vulncheck.com"},{"url":"https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/bookstack-broken-access-control-via-image-gallery-api","label":"disclosure@vulncheck.com"}],"tags":["nvd"],"epss":0.00413,"epssPercentile":0.32797,"ingestedAt":"2026-09-24T20:51:40.223Z","slug":"CVE-2026-67204","body":"## Overview\n\nBookStack 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":29.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}