CVE-2026-48152

Budibase is an open-source low-code platform. Prior to 3.39.0, the single-datasource GET and PUT routes are guarded by generic TABLE READ, not by Builder/Admin permission or datasource-specific ownership/resource checks. The built-in Basic app user role maps to the WRITE permission set, which includes table read/write and query write. A Basic user can therefore read an existing REST datasource, receive redacted authConfigs values, submit an update that changes only config.url while keeping the redacted placeholders, and trigger an existing saved relative-path REST query. During update, mergeConfigs() restores the old stored secret when it sees the redaction placeholder. During query execution, Budibase prefixes the attacker-controlled datasource config.url to the relative query path and applies the resolved stored auth headers. The result is server-side disclosure of the builder-configured REST Authorization secret to an attacker-controlled listener. This vulnerability is fixed in 3.39.0.

Budibase is an open-source low-code platform. Prior to 3.39.0, the single-datasource GET and PUT routes are guarded by generic TABLE READ, not by Builder/Admin permission or datasource-specific ownership/resource checks. The built-in Basic app user role maps to the WRITE permission set, which includes table read/write and query write. A Basic user can therefore read an existing REST datasource, receive redacted authConfigs values, submit an update that changes only config.url while keeping the redacted placeholders, and trigger an existing saved relative-path REST query. During update, mergeConfigs() restores the old stored secret when it sees the redaction placeholder. During query execution, Budibase prefixes the attacker-controlled datasource config.url to the relative query path and applies the resolved stored auth headers. The result is server-side disclosure of the builder-configured REST Authorization secret to an attacker-controlled listener. This vulnerability is fixed in 3.39.0.

Summary

Budibase stores external REST datasource credentials server-side and documents that database credentials are applied server-side and are not exposed in the UI. The REST datasource implementation redacts stored Basic/Bearer/OAuth2 auth secrets before returning datasource data to clients. However, the single-datasource GET and PUT routes are guarded by generic TABLE READ, not by Builder/Admin permission or datasource-specific ownership/resource checks.

The built-in Basic app user role maps to the WRITE permission set, which includes table read/write and query write. A Basic user can therefore read an existing REST datasource, receive redacted authConfigs values, submit an update that changes only config.url while keeping the redacted placeholders, and trigger an existing saved relative-path REST query. During update, mergeConfigs() restores the old stored secret when it sees the redaction placeholder. During query execution, Budibase prefixes the attacker-controlled datasource config.url to the relative query path and applies the resolved stored auth headers. The result is server-side disclosure of the builder-configured REST Authorization secret to an attacker-controlled listener.

Source evidence

• packages/server/src/api/routes/datasource.ts: datasource list/create/delete routes are on builderRoutes, but GET /api/datasources/:datasourceId and PUT /api/datasources/:datasourceId are in authorizedRoutes guarded only by PermissionType.TABLE and PermissionLevel.READ.
• packages/server/src/api/routes/datasource.ts: the :datasourceId routes do not attach datasource-specific resource authorization.
• packages/backend-core/src/security/roles.ts: built-in Basic user maps to BuiltinPermissionID.WRITE.
• packages/backend-core/src/security/permissions.ts: WRITE grants READ/EXECUTE levels and includes QUERY WRITE and TABLE WRITE.
• packages/server/src/api/controllers/datasource.ts: datasourceController.update reads the stored datasource, merges ctx.request.body into it, writes the result back, and returns a redacted copy.
• packages/server/src/sdk/workspace/datasources/datasources.ts: removeSecrets() redacts REST Basic/Bearer/OAuth2 secrets to PASSWORD_REPLACEMENT.
• packages/server/src/sdk/workspace/datasources/datasources.ts: mergeConfigs() restores the old stored auth-secret field when the update body sends the redaction placeholder for the same auth config.
• packages/server/src/integrations/rest.ts: relative REST query paths are prefixed with datasource config.url.
• packages/server/src/integrations/rest.ts: REST execution resolves the selected auth config and applies the resulting auth headers to the outbound request.
• packages/server/src/api/routes/query.ts: saved query execution POST /api/v2/queries/:queryId is guarded by QUERY WRITE, which the Basic role has through the WRITE permission set.

Reproduction outline

No production systems were tested. This is source-backed and has a local static verifier plus a proof helper for an already-running authorized instance.

1. Deploy a current Budibase instance.
2. As a builder/admin, create and publish an app.
3. As the builder/admin, create a REST datasource with:
   • config.url set to a benign legitimate API base URL.
   • a stored REST auth config containing a sentinel secret, such as a Bearer token BUDIBASE_REST_TOKEN_SENTINEL.
4. As the builder/admin, create a saved REST query that uses a relative path and that auth config.
5. Add a non-builder Basic app user.
6. As the Basic user, confirm negative controls:
   • Builder-only datasource list/create/preview routes are denied.
   • The user is not a builder/admin.
7. As the Basic user, call GET /api/datasources/{datasourceId}. The response returns the datasource and redacted auth placeholders, not the raw secret.
8. As the Basic user, call PUT /api/datasources/{datasourceId} with the same redacted datasource body but with…

Budibase is an open-source low-code platform. Prior to 3.39.0, the single-datasource GET and PUT routes are guarded by generic TABLE READ, not by Builder/Admin permission or datasource-specific ownership/resource checks. The built-in Basic app user role maps to the WRITE permission set, which includes table read/write and query write. A Basic user can therefore read an existing REST datasource, receive redacted authConfigs values, submit an update that changes only config.url while keeping the redacted placeholders, and trigger an existing saved relative-path REST query. During update, mergeConfigs() restores the old stored secret when it sees the redaction placeholder. During query execution, Budibase prefixes the attacker-controlled datasource config.url to the relative query path and applies the resolved stored auth headers. The result is server-side disclosure of the builder-configured REST Authorization secret to an attacker-controlled listener. This vulnerability is fixed in 3.39.0.

Budibase is an open-source low-code platform. Prior to 3.39.0, the single-datasource GET and PUT routes are guarded by generic TABLE READ, not by Builder/Admin permission or datasource-specific ownership/resource checks. The built-in Basic app user role maps to the WRITE permission set, which includes table read/write and query write. A Basic user can therefore read an existing REST datasource, receive redacted authConfigs values, submit an update that changes only config.url while keeping the redacted placeholders, and trigger an existing saved relative-path REST query. During update, mergeConfigs() restores the old stored secret when it sees the redaction placeholder. During query execution, Budibase prefixes the attacker-controlled datasource config.url to the relative query path and applies the resolved stored auth headers. The result is server-side disclosure of the builder-configured REST Authorization secret to an attacker-controlled listener. This vulnerability is fixed in 3.39.0.

Summary

Budibase stores external REST datasource credentials server-side and documents that database credentials are applied server-side and are not exposed in the UI. The REST datasource implementation redacts stored Basic/Bearer/OAuth2 auth secrets before returning datasource data to clients. However, the single-datasource GET and PUT routes are guarded by generic TABLE READ, not by Builder/Admin permission or datasource-specific ownership/resource checks.

The built-in Basic app user role maps to the WRITE permission set, which includes table read/write and query write. A Basic user can therefore read an existing REST datasource, receive redacted authConfigs values, submit an update that changes only config.url while keeping the redacted placeholders, and trigger an existing saved relative-path REST query. During update, mergeConfigs() restores the old stored secret when it sees the redaction placeholder. During query execution, Budibase prefixes the attacker-controlled datasource config.url to the relative query path and applies the resolved stored auth headers. The result is server-side disclosure of the builder-configured REST Authorization secret to an attacker-controlled listener.

Source evidence

• packages/server/src/api/routes/datasource.ts: datasource list/create/delete routes are on builderRoutes, but GET /api/datasources/:datasourceId and PUT /api/datasources/:datasourceId are in authorizedRoutes guarded only by PermissionType.TABLE and PermissionLevel.READ.
• packages/server/src/api/routes/datasource.ts: the :datasourceId routes do not attach datasource-specific resource authorization.
• packages/backend-core/src/security/roles.ts: built-in Basic user maps to BuiltinPermissionID.WRITE.
• packages/backend-core/src/security/permissions.ts: WRITE grants READ/EXECUTE levels and includes QUERY WRITE and TABLE WRITE.
• packages/server/src/api/controllers/datasource.ts: datasourceController.update reads the stored datasource, merges ctx.request.body into it, writes the result back, and returns a redacted copy.
• packages/server/src/sdk/workspace/datasources/datasources.ts: removeSecrets() redacts REST Basic/Bearer/OAuth2 secrets to PASSWORD_REPLACEMENT.
• packages/server/src/sdk/workspace/datasources/datasources.ts: mergeConfigs() restores the old stored auth-secret field when the update body sends the redaction placeholder for the same auth config.
• packages/server/src/integrations/rest.ts: relative REST query paths are prefixed with datasource config.url.
• packages/server/src/integrations/rest.ts: REST execution resolves the selected auth config and applies the resulting auth headers to the outbound request.
• packages/server/src/api/routes/query.ts: saved query execution POST /api/v2/queries/:queryId is guarded by QUERY WRITE, which the Basic role has through the WRITE permission set.

Reproduction outline

No production systems were tested. This is source-backed and has a local static verifier plus a proof helper for an already-running authorized instance.

1. Deploy a current Budibase instance.
2. As a builder/admin, create and publish an app.
3. As the builder/admin, create a REST datasource with:
   • config.url set to a benign legitimate API base URL.
   • a stored REST auth config containing a sentinel secret, such as a Bearer token BUDIBASE_REST_TOKEN_SENTINEL.
4. As the builder/admin, create a saved REST query that uses a relative path and that auth config.
5. Add a non-builder Basic app user.
6. As the Basic user, confirm negative controls:
   • Builder-only datasource list/create/preview routes are denied.
   • The user is not a builder/admin.
7. As the Basic user, call GET /api/datasources/{datasourceId}. The response returns the datasource and redacted auth placeholders, not the raw secret.
8. As the Basic user, call PUT /api/datasources/{datasourceId} with the same redacted datasource body but with…