# CVE-2026-95503: Keycloak-services: keycloak-services: potential kdc spoofing bypass when kerberos password authentication is enabled

> Attackers can spoof the KDC to bypass authentication in Keycloak when Kerberos password auth is enabled without SPNEGO, gaining unauthorized access.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Sep 2026
- **Updated:** 22 Sep 2026
- **Also known as:** GHSA-35j3-ccrv-pgvj

## What is CVE-2026-95503?

CVE-2026-95503 is a medium-severity authentication bypass vulnerability in Red Hat Build of Keycloak, published on 22 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in the Kerberos federation provider of Keycloak, an open-source identity and access management solution. When Kerberos password authentication is used without SPNEGO, the system fails to verify the identity of the Key Distribution Center (KDC) by requesting a server ticket. This allows an attacker on the same network to spoof the KDC and bypass the authentication process, potentially gaining unauthorized access to user accounts.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2026-95503?


## How do I fix CVE-2026-95503?

No fix has been published for CVE-2026-95503 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-95503 being exploited?

There is no known exploitation of CVE-2026-95503 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-95503 and fix it if it is affected.

What it is: CVE-2026-95503 is a medium-severity authentication bypass vulnerability in Red Hat Build of Keycloak, published on 22 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-95503 in the wild and no public exploit code.

Affected product: Red Hat 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-2026-95503/ (Markdown: https://insights.sbomify.com/CVE-2026-95503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-95503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-95503
- OSV: https://osv.dev/vulnerability/CVE-2026-95503

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-95503/
Summaries are generated and may contain mistakes; the official description above is the record.