CVE-2026-50132

Budibase has an Account Impersonation Issue — Chat Identity Link Hijacking via Missing Consent & CSRF

Published

2026-06-22

Modified

2026-07-21

EPSS percentile

9%

Aliases

GHSA-v7j5-vc4m-723w

Sources

github-advisory

Summary

## 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 Type - CWE-352: Cross-Site Request Forgery - CWE-284: Improper Access Control --- ## Vulnerability 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 Registration ```typescript // packages/server/src/api/routes/chat.ts:22 router.get( "/api/chat-links/:instance/:token/handoff", controller.handoffChatLinkSession // registered in publicRoutes — zero auth middleware ) ``` ### Vulnerable Controller (full function) ```typescript // packages/server/src/api/controllers/ai/chatIdentityLinks.ts:61–110 export async function handoffChatLinkSession( ctx: UserCtx ) { const token = resolveToken(ctx.params.token) const session = await sdk.ai.chatIdentityLinks.getChatIdentityLinkSession(token) if (!session) { throw new HTTPError("Link token is invalid or has expired", 400) } assertSessionMatchesInstance({ workspaceId: session.workspaceId, instance: ctx.params.instance }) if (!ctx.isAuthenticated) { // Unauthenticated: set return URL cookie, redirect to login // After login, same URL is visited again → attack completes silently utils.setCookie(ctx, `/api/chat-links/${ctx.params.instance}/${token}/handoff`, "budibase:returnurl", { sign: false } // ← unsigned cookie, but not an open redirect ) ctx.redirect("/builder/auth/login") return } const currentGlobalUserId = getCurrentGlobalUserId(ctx) const consumedSession = await sdk.ai.chatIdentityLinks.consumeChatIdentityLinkSession(token) // ↓↓↓ THE VULNERABLE WRITE — no consent check, no CSRF token ↓↓↓ await sdk.ai.chatIdentityLinks.upsertChatIdentityLink({ provider: consumedSession.provider, externalUserId: consumedSession.externalUserId, // ← ATTACKER's Slack ID externalUserName: consumedSession.externalUserName, teamId: consumedSession.teamId, globalUserId: currentGlobalUserId, // ← VICTIM's Budibase user ID linkedBy: currentGlobalUserId, }) ctx.type = "text/html" ctx.body = renderLinkSuccessPage() // ← "Authentication succeeded." — no disclosure to user } ``` -- --- ### Step 1 — Attacker triggers `/link` in Slack Attacker 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):** ```json { "token": "tok_xxxxxxxxxxxxxxxx", "tenantId": "acme", "workspaceId": "ws_abc123", "provider": "slack", "externalUserId": "UA12345678", "externalUserName": "attacker", "teamId": "T_ACME_SLACK", "createdAt": "2026-05-02T10:00:00.000Z", "expiresAt": "2026-05-02T10:10:00.000Z" } ``` Slack DM sent privately to attacker: ``` Link your Slack account to continue chatting with this agent. https://budibase.company.com/api/chat-links/ws_abc123/tok_xxxxxxxxxxx

Affected packages

Remediation: Upgrade to 3.39.0 or later.

References

• https://github.com/advisories/GHSA-v7j5-vc4m-723w