CVE-2026-50137
CriticalCVSS 9.4Exploitation Probability (EPSS)
Low risk33th percentile - higher than 33% of all known CVEs
Summary
Budibase prior to version 3.39.0 contains a vulnerability allowing an anonymous attacker to obtain a pre-signed PUT URL for any S3 bucket the victim has access to. The attack requires knowledge of a workspace ID and S3 datasource ID but no authentication.
Risk Assessment
The risk involves unauthorized write access to the victim's S3 buckets, potentially leading to data leakage, modification, or corruption. Attackers could also leverage this for privilege escalation in the cloud environment.
Recommendation
Upgrade Budibase to version 3.39.0 or later immediately. As a temporary measure, restrict access to the /api/attachments/:datasourceId/url endpoint and enforce authentication for all requests.
Other vulnerabilities in Budibase
See all- CVE-2026-103757High
Budibase through 3.41.0 contains a server-side request forgery vulnerability in AI table generation because the uploadUrl function in packages/server/src/utilities/fileUtils.ts uses raw node-fetch instead of fetchWithBlacklist. Authenticated builder users can send a prompt to POST /api/ai/tables that places an internal URL in an attachment column, causing the server to fetch it and return a presigned object-storage URL containing the response, such as cloud metadata credentials.
- CVE-2026-100688Medium
Budibase server before 3.45.0 contains a cross-tenant information disclosure vulnerability in the GET /api/applications/:appId/appPackage endpoint that allows authenticated users to read another tenant's application metadata and source code. Attackers can supply a victim tenant's app id to retrieve sensitive application details including navigation structure, role names, internal screen URLs, JavaScript snippets, and user identifiers without authorization checks.
- CVE-2026-100684High
Budibase versions 3.41.0 before 3.45.0 contain an authentication bypass in the OIDC/SSO login path of @budibase/server. When no existing user matches the incoming SSO subject, the server looks up pending user invites by the IdP-asserted email address alone — without validating an invite code and without an email_verified check. An attacker who can register at an IdP that the tenant trusts for OIDC and assert a victim's invited email address claims the pending invite and inherits all of its granted privileges, including builder and admin.global.
- CVE-2026-100680High
Budibase versions before 3.45.0 fail to disable external JSON reference resolution in the OpenAPI/Swagger import validator, allowing authenticated builders to read arbitrary local files. Attackers with builder access can embed file:// references in OpenAPI specifications submitted to the import endpoint to exfiltrate sensitive files including environment variables containing JWT secrets, API keys, and database credentials.
- CVE-2026-48152High
Budibase is an open-source low-code platform that prior to version 3.39.0 had security vulnerabilities related to access to GET and PUT routes for single data sources. Basic role users could access sensitive information such as authorization secrets by manipulating configuration data.
- CVE-2026-46427High
Budibase is an open-source low-code platform that prior to version 3.38.3 did not properly mask sensitive data in the Snowflake integration. An authenticated BASIC user could retrieve the full PEM key in plaintext.
- CVE-2026-46426High
Budibase is an open-source low-code platform. Prior to version 3.38.2, the file upload endpoint POST /api/attachments/process does not enforce active-content restrictions for authenticated users, allowing authenticated builders to upload dangerous files.
- CVE-2026-45717High
Budibase prior to version 3.38.1 has a vulnerability in its REST API that allows authenticated app users to modify datasource configurations. Users with BASIC role or higher can send PUT requests to change settings, potentially leading to unauthorized access to sensitive data.
- CVE-2026-45716High
Budibase is an open-source low-code platform that prior to version 3.38.1 had a vulnerability in the POST /api/global/users/onboard endpoint. This allows builder-level users to create new global admin accounts, leading to privilege escalation.
- CVE-2026-45548High
Budibase is an open-source low-code platform. In versions prior to 3.34.8, the processUrlFile function in extract.ts did not validate IP addresses, allowing authenticated users to send requests to internal network addresses.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

