Medium severity · published Mar 27, 2026
CVE-2026-33758
OpenBao has Reflected XSS in its OIDC authentication error message
6.1
CVSS
0.3%
EPSS
No
On KEV
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`.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 22% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
openbao · openbao
< 2.5.2 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33758
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33758
Patch
https://github.com/openbao/openbao/commit/6e2b2dd84f0e47cebc90d6e79609dd5274732662
Issue Tracking
https://github.com/openbao/openbao/pull/2709
Product
https://github.com/openbao/openbao/releases/tag/v2.5.2
Vendor Advisory
https://github.com/openbao/openbao/security/advisories/GHSA-cpj3-3r2f-xj59
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-33758
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2452294
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