CVE-2026-73302: Budibase OIDC SSO account takeover via unverified email claim

CVE-2026-73302 · Severity: medium · CVSS 4 · Published 2026-08-13

Budibase is a low-code application platform that uses OIDC/OAuth for single sign-on authentication. The system links incoming SSO identities to existing Budibase accounts based solely on email address, without verifying that the email has been confirmed by the identity provider. An attacker can exploit this by registering at a configured IdP (such as Keycloak) with an unverified email matching an existing Budibase user, then logging in to take over that user's account, including administrative privileges.

Technologies: @budibase/server (npm). Vendors: npm.

Quick answers

Is CVE-2026-73302 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-73302 being exploited in the wild.
How severe is CVE-2026-73302?
Medium severity, with a CVSS score of 4, published 13 August 2026.
Which products and versions are affected?
@budibase/server (npm) SEMVER:introduced=0,last_affected=3.38.1.
Is there a fix for CVE-2026-73302?
A patch was published on 2026-07-24: Version 3.40.0 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-73302 attacked?
It is attacked over the network.
Am I affected by CVE-2026-73302?
Check whether you run @budibase/server (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability is an authentication bypass in Budibase's OIDC login flow. The SSO handler attempts to match incoming IdP identities by the OIDC subject claim (sub); when that fails (e.g., a fresh attacker account), it silently falls back to matching by email address alone, without consulting the email_verified claim from the ID token. Per OIDC Core §5.7, the email claim must not be used for account linking unless email_verified is true. The vulnerable code paths are in packages/backend-core/src/middleware/passport/sso/oidc.ts (getEmail function at lines 113–135, which never reads email_verified) and sso.ts (fallback matching at lines 57–59). An attacker with access to a trusted IdP that permits self-registration or email editing (common defaults in Keycloak and Authentik) can register or modify an account to claim the victim's email with email_verified=false, then authenticate via Budibase's OIDC flow to inherit the victim's account ID, roles, and permissions. The attack has been reproduced against Budibase 3.39.14 with stock Keycloak. The fix is available in version 3.40.0 and later.

Affected products

  • Budibase Budibase < 3.40.0

Identifiers

  • CVE-2026-73302
  • GHSA-hp6v-6jw7-gv2f

Timeline

  • 2026-07-24: disclosed
  • 2026-07-24: patched: Version 3.40.0 released with fix

References

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