CVE-2026-72856: Budibase before 3.40.0 Authentication Bypass via Tenant Owner Email

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-13 · updated 2026-08-31
Weakness: CWE-640

Description

Budibase versions before 3.40.0 contain an authorization/authentication bypass in the PUT /api/global/users/tenant/owner (changeTenantOwnerEmail) endpoint. On self-hosted instances (SELF_HOSTED or DISABLE_ACCOUNT_PORTAL set), the cloudRestricted middleware is a no-op and the route is protected only by a general authentication check, so any authenticated user — including a lowest-privilege BASIC app user — can reassign the tenant account-holder (top-privilege admin) email to an attacker-controlled address. The attacker can then use the public password-reset flow to take over the admin account, leading to full administrative access.

Affected products

budibase: before 3.40.0 — fixed in 3.40.0

How to fix

Upgrade to a fixed version: budibase 3.40.0. Check the vendor advisory for mitigations.

References

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