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CVE-2026-9801

4.9 · MEDIUM

A flaw was found in Keycloak.

Published May 28, 2026CWE-1284EPSS 0.90%

Overview

CVE-2026-9801 is a medium-severity vulnerability. It was published on May 28, 2026 and has a CVSS 3.1 base score of 4.9 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 4.9, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

A flaw was found in Keycloak. A remote attacker with high privileges, such as a realm administrator configuring a malicious Lightweight Directory Access Protocol (LDAP) server or an attacker compromising an upstream LDAP server, could exploit this vulnerability. By sending a malformed LDAP password policy response during a password authentication request, the attacker can trigger an OutOfMemoryError. This causes the Keycloak Java Virtual Machine (JVM) to terminate, leading to a denial of service (DoS) for all realms on the affected node.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently asked questions

What is CVE-2026-9801?

CVE-2026-9801 is a medium-severity vulnerability. It was published on May 28, 2026 and has a CVSS 3.1 base score of 4.9 (MEDIUM).

How severe is CVE-2026-9801?

This vulnerability has a CVSS 3.1 base score of 4.9, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-9801?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-9801?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-9801 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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