GHSA-v7j5-vc4m-723w: Budibase has an Account Impersonation Issue — Chat Identity Link Hijacking via Missing Consent & CSRF
Title**Chat Identity Link Hijacking — Attacker Can Silently Map Their Slack/Discord Identity to Any Authenticated Budibase User's Account**Severity**High** — CVSS 3.1: AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N = **7.3**Affected Product**Product:** Budibase**Version:** 3.37.2 (introduced in this version)**Component:** `packages/server/src/api/controllers/ai/chatIdentityLinks.ts`**Endpoint:** `GET /api/chat-links/:instance/:token/handoff`Vulnerability TypeCWE-352: Cross-Site Request ForgeryCWE-284: Improper Access ControlVulnerability Description`GET /api/chat-links/:instance/:token/handoff` is a **public endpoint** (no auth required) that performs a permanent, state-changing operation: it binds an external chat identity (Slack/Discord/MS Teams) to an authenticated Budibase user account, with **no consent UI and no CSRF protection**.The session token in the URL is created **by the attacker** (from their own `/link` slash command) and embeds **the attacker's `externalUserId`**. When an authenticated Budibase victim visits the URL, their account is silently and permanently linked to the attacker's Slack/Discord identity. The server responds with `"Authentication succeeded."` — no indication of what was linked.Route RegistrationVulnerable Controller (full function)Proof of Concept — Annotated HTTP TraceSetup| Role | Identity |
|---|---|
| Attacker | Slack user `U_ATTACKER` (e.g. `UA12345678`), Budibase tenant `acme`, workspace ID `ws_abc123` |
| Victim | Budibase admin, session cookie `budibase:session=VICTIM_SESSION` |Step 1 — Attacker triggers `/link` in SlackAttacker types `/link` to the Budibase Slack bot. Budibase server creates a Redis session:**Redis key:** `chatIdentityLinkSession:tok_xxxxxxxxxxxxxxxx`**Redis value (exact structure from `ChatIdentityLinkSession` interface):**Slack DM sent privately to attacker:**Key observation:** This URL embeds the attacker's own `externalUserId` inside the token. The attacker has full control over which identity gets linked.Step 2 — Attacker forwards URL to victimAttacker posts in the company Slack:Step 3 — Victim clicks link (authenticated)**HTTP Request (victim's browser):****HTTP Response:**The victim sees "Authentication succeeded." with no mention of Slack, no mention of `attacker`, no mention of what capabilities were granted.**CouchDB global-db document written immediately after (exact structure from `upsertChatIdentityLink`):**The mapping is now permanent. `externalUserId = UA12345678` (attacker) → `globalUserId = ro_global_us_VICTIM_ADMIN_ID` (victim).Step 4 — Attacker impersonates victim via AI agentAttacker sends any message to the Budibase Slack bot from their own account (`UA12345678`).The chat handler resolves the identity:The attacker can now ask the agent:"Show me all rows in the Customers table"
"Trigger the 'Send Invoice' automation for customer ID 42"
"What files are in the knowledge base?"Each request runs with the victim admin's identity and permissions. The victim has no indication this is happening.Step 3b — Variant: Victim Not Yet AuthenticatedIf the victim is not currently logged in when they click the URL:**HTTP Request:****HTTP Response:**After the victim logs in, the browser follows the return URL and the attack completes identically to Step 3.Impact| Dimension | Detail |
|---|---|
| Confidentiality | **High** — attacker reads all table rows, files, and knowledge base data accessible to victim |
| Integrity | **High** — attacker writes rows and triggers automations (email, external API calls, record creation) as victim |
| Availability | None |
| Auth required | **Low** — attacker only needs a Slack/Discord account in the same workspace as the Budibase bot |
| User interaction | **Required** — victim clicks one link (trivial social engineering in any enterprise Slack) |
| Scope | Unchanged — impact is within the victim's Budibase tenant |
| Persistence | **Permanent** — the link document persists in CouchDB until explicitly deleted; re-exploitation survives token rotation |Why Severity Is High (Not Medium)The social engineering bar is near zero in enterprise Slack:The link looks like a legitimate Budibase URL on the company domainThe message pattern ("link your account for AI agent access") matches the product's own UXA victim who clicks and sees "Authentication succeeded." has no reason to be suspiciousThe effect is **permanent and silent** — the victim never learns their account was linkedCombined with admin-level access to all application data and automation triggers, this meets the bar for High.RemediationMinimum Fix — Add Consent PageConvert the handoff to a two-step flow:Moving the write to `POST` removes it from `publicRoutes`, making Budibase's existing CSRF middleware apply automatically.Additional HardeningShow the `externalUserName` and provider on the consent pageLog the event to the audit trail (both identities, timestamp, IP)Optionally restrict linking to users with explicit permission (not all roles)Credits,
Vishal Kumar B
https://github.com/VishaaLlKumaaRrReferences`packages/server/src/api/routes/chat.ts:22` — public route registration`packages/server/src/api/controllers/ai/chatIdentityLinks.ts:61–110` — full vulnerable controller`packages/server/src/sdk/workspace/ai/chatIdentityLinks.ts:135–165` — session creation (embeds attacker's externalUserId)`packages/server/src/sdk/workspace/ai/chatIdentityLinks.ts:202–247` — upsertChatIdentityLink (permanent write)`packages/server/src/api/controllers/webhook/chatHandler.ts:421` — identity resolution during agent message handling`packages/server/src/ai/tools/budibase/automations.ts` — automation trigger capability`packages/server/src/ai/tools/budibase/rows.ts` — row read/write capability`packages/types/src/sdk/chatIdentityLinks.ts` — session + link type definitionsCWE-352: Cross-Site Request ForgeryCWE-284: Improper Access Control
CVSS v3.1: 7.3