CVE-2026-9801

What it is

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.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. High risk of service disruption.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-28 06:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 12:10 UTC Last updatedMost recent change to the record

Details

Published

2026-05-28 06:16 UTC

Last modified

2026-10-26 12:10 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-1284

Record status

Modified

Affected

• Redhat Build Of Keycloak

Attack profile CVSS 3.1 · 4.9

Attack vector

Network

Complexity

Low

Privileges needed

High

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High