CVE-2026-9801 — MEDIUM (4.9)

Vulnerability 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.

CVSS Score

4.9

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Affected Products

Vendor	Product	Versions
Redhat	Build Of Keycloak	-

Related Weaknesses (CWE)

CWE-1284

References

https://access.redhat.com/errata/RHSA-2026:25097
https://access.redhat.com/errata/RHSA-2026:25098
https://access.redhat.com/errata/RHSA-2026:30049
https://access.redhat.com/errata/RHSA-2026:30050
https://access.redhat.com/security/cve/CVE-2026-9801MitigationVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2482473Issue TrackingVendor Advisory

FAQ

What is CVE-2026-9801?

CVE-2026-9801 is a vulnerability with a CVSS score of 4.9 (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 compromis...

How severe is CVE-2026-9801?

CVE-2026-9801 has been rated MEDIUM with a CVSS base score of 4.9/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-9801?

Check the references section above for vendor advisories and patch information. Affected products include: Redhat Build Of Keycloak.