{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "26.05.4"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "cec78b1bcf096a74bf0a79fae3f884dc1d0803e4"
            }
          ],
          "repo": "https://github.com/bookstackapp/bookstack",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-863"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67204.json"
  },
  "details": "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.",
  "id": "CVE-2026-67204",
  "modified": "2026-08-30T11:30:29.780954553Z",
  "published": "2026-08-24T15:33:13.649Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://codeberg.org/bookstack/bookstack/releases/tag/v26.05.4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67204.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-67204"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/bookstack-broken-access-control-via-image-gallery-api"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/BookStackApp/BookStack"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "BookStack \u003c 26.05.4 Broken Access Control via Image Gallery API"
}