What’s Vulnerable › Vulnerabilities

CVE-2026-33758: OpenBao has Reflected XSS in its OIDC authentication error message

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% 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-20

Description

OpenBao is an open source identity-based secrets management system. Prior to version 2.5.2, OpenBao installations that have an OIDC/JWT authentication method enabled and a role with `callback_mode=direct` configured are vulnerable to XSS via the `error_description` parameter on the page for a failed authentication. This allows an attacker access to the token used in the Web UI by a victim. The `error_description` parameter has been replaced with a static error message in v2.5.2. The vulnerability can be mitigated by removing any roles with `callback_mode` set to `direct`.

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://github.com/openbao/openbao/commit/6e2b2dd84f0e47cebc90d6e79609dd5274732662
• https://github.com/openbao/openbao/pull/2709
• https://github.com/openbao/openbao/releases/tag/v2.5.2
• https://github.com/openbao/openbao/security/advisories/GHSA-cpj3-3r2f-xj59
• https://access.redhat.com/security/cve/CVE-2026-33758
• https://bugzilla.redhat.com/show_bug.cgi?id=2452294
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33758.json

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