In deployments of WSO2 Identity Server configured with a case-insensitive user store and a case-sensitive database for identity data, mismatches in username case handling can occur. This inconsistency results in OAuth token revocation operations failing to correctly identify usernames containing mixed-case characters during certain lifecycle events, preventing tokens from being invalidated.

A malicious actor can exploit this vulnerability by possessing a valid access or refresh token associated with a mixed-case username. In affected configurations, these tokens may not be revoked when expected. The actor can then leverage these unrevoked tokens, before their expiry, to continue performing actions that should have been restricted, effectively bypassing intended access controls.

Project Subscriptions

Vendors Products
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Advisories

No advisories yet.

Fixes

Solution

Follow the instructions given on https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5387/#solution


Workaround

No workaround given by the vendor.

History

Wed, 28 Oct 2026 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Wso2 identity Server
Vendors & Products Wso2 identity Server

Wed, 28 Oct 2026 19:30:00 +0000

Type Values Removed Values Added
Description In deployments of WSO2 Identity Server configured with a case-insensitive user store and a case-sensitive database for identity data, mismatches in username case handling can occur. This inconsistency results in OAuth token revocation operations failing to correctly identify usernames containing mixed-case characters during certain lifecycle events, preventing tokens from being invalidated. A malicious actor can exploit this vulnerability by possessing a valid access or refresh token associated with a mixed-case username. In affected configurations, these tokens may not be revoked when expected. The actor can then leverage these unrevoked tokens, before their expiry, to continue performing actions that should have been restricted, effectively bypassing intended access controls.
Title Incomplete OAuth Token Revocation via Case Mismatch in WSO2 Identity Server Allows Continued Access After Lifecycle Events
First Time appeared Wso2
Wso2 wso2 Carbon Oauth
Wso2 wso2 Identity Server
Weaknesses CWE-613
CPEs cpe:2.3:a:wso2:wso2_carbon_oauth:*:*:*:*:*:*:*:*
cpe:2.3:a:wso2:wso2_identity_server:*:*:*:*:*:*:*:*
Vendors & Products Wso2
Wso2 wso2 Carbon Oauth
Wso2 wso2 Identity Server
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: WSO2

Published:

Updated: 2026-10-28T19:21:35.702Z

Reserved: 2026-04-20T05:10:27.014Z

Link: CVE-2026-6647

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-28T20:18:44.080

Modified: 2026-10-28T20:18:44.080

Link: CVE-2026-6647

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-28T21:15:15Z

Weaknesses