---
id: CVE-2026-33758
aliases:
  - GHSA-cpj3-3r2f-xj59
  - BIT-openbao-2026-33758
  - GO-2026-4862
title: OpenBao has Reflected XSS in its OIDC authentication error message
summary: OpenBao has Reflected XSS in its OIDC authentication error message
severity: critical
vendor: openbao
product: github.com/openbao/openbao
ecosystem: go
affected:
  - github.com/openbao/openbao < 0.0.0-20260325133417-6e2b2dd84f0e
patched:
  - github.com/openbao/openbao 0.0.0-20260325133417-6e2b2dd84f0e
published: '2026-03-26'
updated: '2026-07-27'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-cpj3-3r2f-xj59'
references:
  - url: 'https://github.com/openbao/openbao/security/advisories/GHSA-cpj3-3r2f-xj59'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-33758'
  - url: 'https://github.com/openbao/openbao/pull/2709'
  - url: >-
      https://github.com/openbao/openbao/commit/6e2b2dd84f0e47cebc90d6e79609dd5274732662
  - url: 'https://github.com/openbao/openbao'
  - url: 'https://github.com/openbao/openbao/releases/tag/v2.5.2'
tags:
  - osv
  - go
epss: 0.00449
epssPercentile: 0.36403
ingestedAt: '2026-07-27T19:08:54.642Z'
---

## Overview

### Impact

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.

### Patches
The `error_description` parameter has been replaced with a static error message in v2.5.2

### Workarounds
The vulnerability can be mitigated by removing any roles with `callback_mode` set to `direct`.

## Affected packages

- `github.com/openbao/openbao < 0.0.0-20260325133417-6e2b2dd84f0e`

## Remediation

Upgrade to a patched release:

- `github.com/openbao/openbao 0.0.0-20260325133417-6e2b2dd84f0e`