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CVE-2026-9801

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

Published: May 28, 2026Updated: May 28, 2026 Sources: CVE List NVD
NVD MITRE
4.9CVSS
MEDIUM

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.

EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Workaround Only

CVSS Vector Breakdown

AV:NAC:LPR:HUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:HPrivileges Required
High
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High

Weaknesses

CWE-1284

Affected Products

Red Hat Build of Keycloak
Red Hat

Exploitability

Workaround Available

References

https://access.redhat.com/security/cve/CVE-2026-9801
access.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2482473
bugzilla.redhat.com

Timeline

Published
May 28, 2026
Last Updated
May 28, 2026

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