# CVE-2026-6647: In deployments of WSO2 Identity Server configured with a case-insensitive user store and a case-sensitive database for identity data, mismat


- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 28 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-rxrw-f2xj-7fjx

## What is CVE-2026-6647?

CVE-2026-6647 is a high-severity vulnerability in WSO2 Carbon OAuth, published on 28 Oct 2026. 

### Official 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.

Weakness: CWE-613 (DEPRECATED: Insufficient Session Expiration)

## Which versions are affected by CVE-2026-6647?


## How do I fix CVE-2026-6647?

No fix has been published for CVE-2026-6647 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6647 being exploited?

There is no known exploitation of CVE-2026-6647 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6647 and fix it if it is affected.

What it is: CVE-2026-6647 is a high-severity vulnerability in WSO2 Carbon OAuth, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-6647 in the wild and no public exploit code.

Affected product: WSO2 Carbon OAuth. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-6647/ (Markdown: https://insights.sbomify.com/CVE-2026-6647/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6647
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6647
- OSV: https://osv.dev/vulnerability/CVE-2026-6647

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6647/
Summaries are generated and may contain mistakes; the official description above is the record.