---
id: CVE-2026-6647
title: >-
  Incomplete OAuth Token Revocation via Case Mismatch in WSO2 Identity Server
  Allows Continued Access After Lifecycle Events
summary: >-
  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
  op…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L'
cvssSource: cna
cwe:
  - CWE-613
vendor: WSO2
product: WSO2 Identity Server
affected:
  - identity_server >= 7.2.0 < 7.2.0.21
  - >-
    org.wso2.carbon.identity.inbound.auth.oauth2:org.wso2.carbon.identity.oauth
    >= 7.0.385 < 7.0.385.17
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-29T01:51:34.435159Z'
published: '2026-10-28'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T02:02:13.994Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-6647'
references:
  - url: >-
      https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5387/
tags:
  - cve.org
epss: 0.00212
epssPercentile: 0.11566
ingestedAt: '2026-10-31T01:14:13.032Z'
---

## Overview

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.

## Affected

- `identity_server >= 7.2.0 < 7.2.0.21`
- `org.wso2.carbon.identity.inbound.auth.oauth2:org.wso2.carbon.identity.oauth >= 7.0.385 < 7.0.385.17`

## Remediation

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