OpenBao lacks user confirmation for OIDC direct callback mode
Date: 2026-03
Affected: go/github.com/openbao/openbao
Attack vector: phishing
Category: vulnerability-disclosure
Severity: Critical
CVE: CVE-2026-33757
CWE: CWE-384
CVSS: 9.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L)

### Impact OpenBao does not prompt for user confirmation when logging in via JWT/OIDC and a role with `callback_mode` set to `direct`. This allows an attacker to start an authentication request and perform "remote phishing" by having the victim visit the URL and automatically log-in to the session of the attacker. Despite being based on the authorization code flow, the `direct` mode calls back directly to the API and allows an attacker to poll for an OpenBao token until it is issued. ### Patches Version 2.5.2 includes an additional confirmation screen for `direct` type logins that requires manual user interaction in order to finish the authentication. ### Workarounds This issue can be worked around either by removing any roles with `callback_mode=direct` or enforcing confirmation for every session on the token issuer side for the Client ID used by OpenBao.


Mitigations:

Architectural layers (MAESTRO):