OpenBao has Reflected XSS in its OIDC authentication error message

Summary

CVECVE-2026-33758
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-27 15:16:57 UTC
Updated2026-03-30 17:21:54 UTC
DescriptionOpenBao 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`.

Risk And Classification

Primary CVSS: v4.0 9.4 CRITICAL from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.000830000 probability, percentile 0.243580000 (date 2026-04-01)

Problem Types: CWE-20 | CWE-79 | CWE-116 | 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


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary9.4CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/C...
4.0CNADECLARED9.4CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
3.1[email protected]Primary6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Passive
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
High
Sub Integrity
High
Sub Availability
High

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Openbao Openbao All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Openbao Openbao affected < 2.5.2 Not specified

References

ReferenceSourceLinkTags
github.com/openbao/openbao/security/advisories/GHSA-cpj3-3r2f-xj59 [email protected] github.com Vendor Advisory
github.com/openbao/openbao/pull/2709 [email protected] github.com Issue Tracking, Patch
github.com/openbao/openbao/commit/6e2b2dd84f0e47cebc90d6e79609dd5274732662 [email protected] github.com Patch
github.com/openbao/openbao/releases/tag/v2.5.2 [email protected] github.com Product, Release Notes
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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