CVE-2026-33758

Summary

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 Software

Weaknesses

• CWE-20: CWE-20: Improper Input Validation
• CWE-79: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
• CWE-116: CWE-116: Improper Encoding or Escaping of Output

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: total

OpenBao: reflected XSS in OpenBao OIDC authentication error message

Additional References

• 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

References

• https://github.com/openbao/openbao/security/advisories/GHSA-cpj3-3r2f-xj59
• https://github.com/openbao/openbao/pull/2709
• https://github.com/openbao/openbao/commit/6e2b2dd84f0e47cebc90d6e79609dd5274732662
• https://github.com/openbao/openbao/releases/tag/v2.5.2

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