{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-67204",
        "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "state": "PUBLISHED",
        "assignerShortName": "VulnCheck",
        "dateReserved": "2026-07-28T16:06:49.775Z",
        "datePublished": "2026-08-24T15:33:13.649Z",
        "dateUpdated": "2026-08-24T15:33:13.649Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
                "shortName": "VulnCheck",
                "dateUpdated": "2026-08-24T15:33:13.649Z"
            },
            "title": "BookStack < 26.05.4 Broken Access Control via Image Gallery API",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "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."
                }
            ],
            "tags": [
                "x_open-source"
            ],
            "datePublic": "2026-08-24T00:00:00.000Z",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "cweId": "CWE-863",
                            "description": "Incorrect Authorization",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "defaultStatus": "affected",
                    "vendor": "BookStackApp",
                    "product": "BookStack",
                    "packageURL": "pkg:github/BookStackApp/BookStack",
                    "repo": "https://github.com/BookStackApp/BookStack",
                    "versions": [
                        {
                            "status": "affected",
                            "version": "0",
                            "versionType": "custom",
                            "lessThan": "26.05.4"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ],
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "privilegesRequired": "LOW",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "LOW",
                        "subIntegrityImpact": "NONE",
                        "vulnAvailabilityImpact": "LOW",
                        "subAvailabilityImpact": "NONE",
                        "exploitMaturity": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "valueDensity": "NOT_DEFINED",
                        "vulnerabilityResponseEffort": "NOT_DEFINED",
                        "providerUrgency": "NOT_DEFINED",
                        "version": "4.0",
                        "baseSeverity": "MEDIUM",
                        "baseScore": 5.3,
                        "vectorString": "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"
                    }
                },
                {
                    "format": "CVSS",
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                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ],
                    "cvssV3_1": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "LOW",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "LOW",
                        "availabilityImpact": "LOW",
                        "version": "3.1",
                        "baseSeverity": "MEDIUM",
                        "baseScore": 5.4,
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L"
                    }
                }
            ],
            "references": [
                {
                    "url": "https://www.bookstackapp.com/blog/bookstack-release-v26-05-4/",
                    "name": "Maintainer Blog",
                    "tags": [
                        "vendor-advisory"
                    ]
                },
                {
                    "url": "https://codeberg.org/bookstack/bookstack/releases/tag/v26.05.4",
                    "name": "Codeberg Release Notes",
                    "tags": [
                        "release-notes"
                    ]
                },
                {
                    "url": "https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4",
                    "name": "GitHub Release Notes",
                    "tags": [
                        "release-notes"
                    ]
                },
                {
                    "url": "https://www.vulncheck.com/advisories/bookstack-broken-access-control-via-image-gallery-api",
                    "tags": [
                        "third-party-advisory"
                    ]
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "ByteMe.Red",
                    "type": "finder"
                },
                {
                    "lang": "en",
                    "value": "VulnCheck",
                    "type": "coordinator"
                }
            ],
            "source": {
                "discovery": "UNKNOWN"
            },
            "x_generator": {
                "engine": "vulncheck"
            }
        }
    }
}