XSS in Openbao
CVE-2026-33758
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`.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (36.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.002
Affected products
- Openbao — versions < 2.5.2
Weakness classification (CWE)
References
- github.com/openbao/openbao/security/advisories/GHSA-cpj3-3r2f-xj59 (Vendor Advisory)
- github.com/openbao/openbao/pull/2709 (Patch, Issue Tracking)
- github.com/openbao/openbao/commit/6e2b2dd84f0e47cebc90d6e79609dd5274732662 (Patch)
- github.com/openbao/openbao/releases/tag/v2.5.2 (Product, Release Notes)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-33758?
- CVE-2026-33758 is a medium-severity vulnerability in Openbao, classified under Improper Input Validation. CVSS score: 6.1/10. Published 2026-03-27.
- How severe is CVE-2026-33758?
- Medium severity. CVSS v3 base score is 6.1 out of 10.