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CVE-2026-33757: OpenBao lacks user confirmation for OIDC direct callback mode

• Severity: high (CVSS 8.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-27 · updated 2026-07-15
• Weakness: CWE-384

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.

Affected products

• openbao: before 2.5.2 — fixed in 2.5.2

How to fix

Upgrade to a fixed version: openbao 2.5.2. Check the vendor advisory for mitigations.

References

• https://datatracker.ietf.org/doc/html/rfc8628#section-5.4
• https://github.com/openbao/openbao/commit/e32103951925723e9787e33886ab6b6ec20f4964
• https://github.com/openbao/openbao/security/advisories/GHSA-7q7g-x6vg-xpc3
• https://access.redhat.com/security/cve/CVE-2026-33757
• https://bugzilla.redhat.com/show_bug.cgi?id=2452269
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33757.json

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