# CVE-2023-0091: Keycloak has lack of validation of access token on client registrations endpoint

> Attackers can access or modify sensitive information by exploiting improper client token revocation checks in Keycloak's credential flow.

- **Severity:** Low 3.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Jan 2023
- **Updated:** 9 Apr 2025
- **Also known as:** GHSA-v436-q368-hvgg

## What is CVE-2023-0091?

CVE-2023-0091 is a low-severity missing authorization vulnerability in Redhat Keycloak, published on 11 Jan 2023. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A flaw was found in Keycloak, where it did not properly check client tokens for possible revocation in its client credential flow. This flaw allows an attacker to access or modify potentially sensitive information.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2023-0091?

2 open source packages ship an affected version, including org.keycloak:keycloak-core. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.keycloak:keycloak-core` | Maven | All versions | 20.0.3 |
| `org.keycloak:keycloak-core` | Maven | All versions | 20.0.3 |

Products: Redhat Keycloak.

## How do I fix CVE-2023-0091?

Upgrade org.keycloak:keycloak-core to 20.0.3 or later.

## Is CVE-2023-0091 being exploited?

There is no known exploitation of CVE-2023-0091 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Keycloak

- [CVE-2022-4361](https://insights.sbomify.com/CVE-2022-4361/): Keycloak vulnerable to cross-site scripting when validating URI-schemes on SAML and OIDC (critical 10.0)
- [CVE-2022-1245](https://insights.sbomify.com/CVE-2022-1245/): Keycloak vulnerable to privilege escalation on Token Exchange feature (critical 9.8)
- [CVE-2021-20195](https://insights.sbomify.com/CVE-2021-20195/): keycloak Self Stored Cross-site Scripting vulnerability (critical 9.6)
- [CVE-2019-14910](https://insights.sbomify.com/CVE-2019-14910/): Keycloak Authentication Error (critical 9.3)
- [CVE-2019-14909](https://insights.sbomify.com/CVE-2019-14909/): Keycloak Authentication Error (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-0091 and fix it if it is affected.

What it is: CVE-2023-0091 is a low-severity missing authorization vulnerability in Redhat Keycloak, published on 11 Jan 2023. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-0091 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.keycloak:keycloak-core (Maven): affected all versions; fixed in 20.0.3
- org.keycloak:keycloak-core (Maven): affected all versions; fixed in 20.0.3

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-2023-0091/ (Markdown: https://insights.sbomify.com/CVE-2023-0091/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-0091
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-0091
- OSV: https://osv.dev/vulnerability/CVE-2023-0091

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-0091/
Summaries are generated and may contain mistakes; the official description above is the record.