# CVE-2026-16093: Auth bypass in Red Hat Data Grid 8

> Attackers with valid credentials can bypass signed JWT policies by sending unsigned headers, allowing authentication via weaker client secret methods.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/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:** Yes
- **Published:** 17 Jul 2026
- **Updated:** 16 Sep 2026
- **Also known as:** BIT-keycloak-2026-16093, CLEANSTART-2026-AH74122, GHSA-jmhg-9c54-p575

## What is CVE-2026-16093?

CVE-2026-16093 is a medium-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 17 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with valid client credentials can provide a fake, unsigned assertion header that tricks the system into thinking the policy requirements have been met. This allows the attacker to authenticate using simpler methods like a client secret even when the administrator has mandated more secure, signed assertions.

Weakness: CWE-807 (Reliance on Untrusted Inputs in a Security Decision)

## Which versions are affected by CVE-2026-16093?

1 open source package ship an affected version, including keycloak. It affects 4 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `keycloak` | Bitnami | All versions | 26.7.3 |

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

## How do I fix CVE-2026-16093?

Upgrade keycloak to 26.7.3 or later.

## Is CVE-2026-16093 being exploited?

There is no known exploitation of CVE-2026-16093 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-2026-16093 and fix it if it is affected.

What it is: CVE-2026-16093 is a medium-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 17 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-2026-16093 in the wild and no public exploit code.

Affected packages and fixed versions:
- keycloak (Bitnami): affected all versions; fixed in 26.7.3

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-2026-16093/ (Markdown: https://insights.sbomify.com/CVE-2026-16093/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-16093
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-16093
- OSV: https://osv.dev/vulnerability/CVE-2026-16093

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-16093/
Summaries are generated and may contain mistakes; the official description above is the record.