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CVE-2026-33757

Openbao vulnerability

9.6 CRITICALEPSS 0.61%
  1. Published27 Mar 2026

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 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L

Affected products

Openbao< 2.5.2

Remediation

Fixed in
Openbao≥ 2.5.2

References

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Frequently asked

Is CVE-2026-33757 being actively exploited?

CVE-2026-33757 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.61%.

How severe is CVE-2026-33757?

CVE-2026-33757 has a CVSS 3.1 base score of 9.6, rated critical. EPSS estimates a 0.61% probability of exploitation.

Which products are affected by CVE-2026-33757?

Affected products include Openbao.

How do I fix CVE-2026-33757?

Upgrade affected software to a fixed version, for example Openbao 2.5.2 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-33757 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.