# CVE-2026-4366: Keycloak-services: blind server-side request forgery (ssrf) via http redirect handling in keycloak

> Attackers can exploit improper HTTP redirect handling in Keycloak to access internal resources and cloud metadata, leading to information disclosure.

- **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Mar 2026
- **Updated:** 9 Jun 2026
- **Also known as:** GHSA-g2qr-3mxm-86jj

## What is CVE-2026-4366?

CVE-2026-4366 is a medium-severity server-side request forgery vulnerability in Redhat Build of Keycloak, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was identified in Keycloak, an identity and access management solution, where it improperly follows HTTP redirects when processing certain client configuration requests. This behavior allows an attacker to trick the server into making unintended requests to internal or restricted resources. As a result, sensitive internal services such as cloud metadata endpoints could be accessed. This issue may lead to information disclosure and enable attackers to map internal network infrastructure.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-4366?

It affects 4 products.


Products: Redhat Build of Keycloak, Redhat Jboss Enterprise Application Platform, Redhat Jboss Enterprise Application Platform Expansion Pack, Redhat Single Sign-On.

## How do I fix CVE-2026-4366?

No fix has been published for CVE-2026-4366 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4366 being exploited?

There is no known exploitation of CVE-2026-4366 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-2026-4366 and fix it if it is affected.

What it is: CVE-2026-4366 is a medium-severity server-side request forgery vulnerability in Redhat Build of Keycloak, published on 18 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-4366 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-2026-4366/ (Markdown: https://insights.sbomify.com/CVE-2026-4366/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4366
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4366
- OSV: https://osv.dev/vulnerability/CVE-2026-4366

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-4366/
Summaries are generated and may contain mistakes; the official description above is the record.