# CVE-2026-18207: Keycloak-services: keycloak-services: client policy source-group condition bypass via duplicate group name matching

> Attackers with client management privileges can bypass security policies by exploiting duplicate group names, allowing unauthorized client registration or updates.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Jul 2026
- **Updated:** 31 Aug 2026
- **Also known as:** GHSA-rfxv-6gx8-3fm6

## What is CVE-2026-18207?

CVE-2026-18207 is a medium-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 29 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A flaw was found in the client policy enforcement mechanism of Keycloak. The issue occurs when the system checks group membership by name instead of a unique identifier. An attacker with client management privileges could bypass security policies by joining a group with a matching name in a different part of the group hierarchy, potentially allowing them to register or update clients without following required security hardening profiles.

Weakness: CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2026-18207?

It affects 1 product.


Products: Redhat Build of Keycloak.

## How do I fix CVE-2026-18207?

No fix has been published for CVE-2026-18207 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-18207 being exploited?

There is no known exploitation of CVE-2026-18207 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Build of Keycloak

- [CVE-2026-15572](https://insights.sbomify.com/CVE-2026-15572/): Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation (high 8.8)
- [CVE-2026-3047](https://insights.sbomify.com/CVE-2026-3047/): Keycloak SAML Broken has Authentication Bypass by Primary Weakness (high 8.8)
- [CVE-2026-15573](https://insights.sbomify.com/CVE-2026-15573/): Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher (high 8.1)
- [CVE-2026-16102](https://insights.sbomify.com/CVE-2026-16102/): Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers (high 8.1)
- [CVE-2026-1609](https://insights.sbomify.com/CVE-2026-1609/): Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18207 and fix it if it is affected.

What it is: CVE-2026-18207 is a medium-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 29 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-18207 in the wild and no public exploit code.

Affected product: Redhat Build of Keycloak. 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-2026-18207/ (Markdown: https://insights.sbomify.com/CVE-2026-18207/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18207
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18207
- OSV: https://osv.dev/vulnerability/CVE-2026-18207

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18207/
Summaries are generated and may contain mistakes; the official description above is the record.