High severity · published Mar 27, 2026
CVE-2026-33757
OpenBao lacks user confirmation for OIDC direct callback mode
8.3
CVSS
0.4%
EPSS
No
On KEV
Description
OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, 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. Version 2.5.2 includes an additional confirmation screen for `direct` type logins that requires manual user interaction in order to finish the authentication. 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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
openbao · openbao
< 2.5.2 · source: vendor, NVD