{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-50137",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-03T18:49:32.275Z",
        "datePublished": "2026-06-26T20:41:03.443Z",
        "dateUpdated": "2026-06-29T13:18:45.580Z"
    },
    "containers": {
        "cna": {
            "title": "Budibase: POST /api/attachments/:datasourceId/url is unauthenticated and lets anonymous callers mint S3 PUT pre-signed URLs using stored datasource IAM credentials",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-862",
                            "lang": "en",
                            "description": "CWE-862: Missing Authorization",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "HIGH",
                        "attackRequirements": "NONE",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "HIGH",
                        "vulnAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "baseScore": 8.2,
                        "baseSeverity": "HIGH",
                        "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
                        "version": "4.0"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/Budibase/budibase/security/advisories/GHSA-35c4-rvc8-frhm",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/Budibase/budibase/security/advisories/GHSA-35c4-rvc8-frhm"
                }
            ],
            "affected": [
                {
                    "vendor": "Budibase",
                    "product": "budibase",
                    "versions": [
                        {
                            "version": "< 3.39.0",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-06-26T20:41:03.443Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Budibase is an open-source low-code platform. Prior to 3.39.0, an anonymous attacker who knows or can enumerate a workspace id (app_...) and an S3-source datasource id (ds_...) can call this endpoint with no auth and obtain a 15-minute pre-signed PUT URL minted on the victim's IAM identity. The endpoint also returns the publicUrl so the attacker knows exactly where their PUT lands. Because bucket is attacker-controlled, the attacker can write to any bucket those IAM credentials can write to, not only the bucket the datasource was configured for. The Budibase server route POST /api/attachments/:datasourceId/url (packages/server/src/api/routes/static.ts) is registered with only the recaptcha middleware. There is no authorized(...) middleware in the chain. The controller (packages/server/src/api/controllers/static/index.ts::getSignedUploadURL) looks the requested datasource up, instantiates an AWS S3 client with the datasource's stored accessKeyId / secretAccessKey, and returns an AWS Signature V4 pre-signed PutObjectCommand URL for the caller-supplied bucket and key. The bucket is not pinned to the datasource's configured bucket. The workspace context required by sdk.datasources.get is sourced by getWorkspaceIdFromCtx (packages/backend-core/src/utils/utils.ts) from any of: the x-budibase-app-id header, the JSON body appId, a path segment that begins with the workspace prefix, or ?appId=. auth.buildAuthMiddleware([], { publicAllowed: true }) runs before any of this and explicitly allows anonymous requests. The currentWorkspace middleware's \"deny access to dev preview\" branch only triggers under isBrowser(ctx) && !isApiKey(ctx); isBrowser checks the parsed User-Agent for a recognised browser, so any non-browser client (curl, the supplied PoC, any tool not setting a browser UA) is neither and reaches dev workspaces too. This vulnerability is fixed in 3.39.0."
                }
            ],
            "source": {
                "advisory": "GHSA-35c4-rvc8-frhm",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/Budibase/budibase/security/advisories/GHSA-35c4-rvc8-frhm",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-06-29T13:18:15.171583Z",
                                "id": "CVE-2026-50137",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "total"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-06-29T13:18:45.580Z"
                }
            }
        ]
    }
}