CVE-2026-9801

MEDIUM

Keycloak: keycloak: denial of service via malformed ldap password policy response

Title source: cna
STIX 2.1

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.

References (6)

Core 6
Core References
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:25097
https://access.redhat.com/errata/RHSA-2026:25097
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:25098
https://access.redhat.com/errata/RHSA-2026:25098
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:30049
https://access.redhat.com/errata/RHSA-2026:30049
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:30050
https://access.redhat.com/errata/RHSA-2026:30050
Vdb Entry, X_Refsource_Redhat vdb-entry x_refsource_redhat
https://access.redhat.com/security/cve/CVE-2026-9801
Issue Tracking, X_Refsource_Redhat issue-tracking x_refsource_redhat
RHBZ#2482473
https://bugzilla.redhat.com/show_bug.cgi?id=2482473

Scores

CVSS v3 4.9
EPSS 0.0048
EPSS Percentile 38.7%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-1284
Status published
Products (12)
org.keycloak/keycloak-ldap-federation 0 - 26.6.3Maven
Red Hat/Red Hat Build of Keycloak
Red Hat/Red Hat build of Keycloak 26.4 26.4-19
Red Hat/Red Hat build of Keycloak 26.4 26.4.13-1
Red Hat/Red Hat build of Keycloak 26.4.13
Red Hat/Red Hat build of Keycloak 26.6 26.6-6
Red Hat/Red Hat build of Keycloak 26.6 26.6-8
Red Hat/Red Hat build of Keycloak 26.6 26.6.3-3
Red Hat/Red Hat build of Keycloak 26.6 26.6.4-2
Red Hat/Red Hat build of Keycloak 26.6.3
... and 2 more
Published May 28, 2026
Tracked Since May 28, 2026