CVE-2026-9801

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

Published: May 28, 2026Updated: Jun 26, 2026 Sources: CVE List NVDCWE-1284

4.9MEDIUM

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.

No summary for this CVE yet.

CVSS Vector Breakdown

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

Open in CVSS calculator →

Weaknesses

CWE-1284

Affected Products

Red Hat

commercial·USaka redhat

Red Hat build of Keycloak 26.4On-premWeb App

Web & CMS Plugins

Red Hat build of Keycloak 26.4.13On-prem

DevTools & CI

Red Hat build of Keycloak 26.6On-prem

Security Products / identity-access-mgmt

Red Hat build of Keycloak 26.6.3On-prem

Security Products / identity-access-mgmt

build of keycloakOn-prem

Operating Systems / linux-distro

Exploitability

Official Patch Available

Workaround Available

Is your org exposed to CVE-2026-9801?Request an assessment to establish which checks are appropriate for your systems. Check my exposure

References

https://access.redhat.com/errata/RHSA-2026:25097

access.redhat.com

https://access.redhat.com/errata/RHSA-2026:25098

access.redhat.com

https://access.redhat.com/errata/RHSA-2026:30049

access.redhat.com

and 3 more references View all →

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-9801 and every CVE in our database. Create a free account — no credit card required.

Create Free Account

Plain-language analysis

Impact assessment and exploitation scenario in plain English

Attack graph visualization

Interactive attack path and kill chain mapping

Exploit details & PoC links

ExploitDB, Metasploit, GitHub PoCs with direct links

Nuclei scanner templates

Ready-to-use vulnerability scanner templates

Full remediation guide

Patch instructions, workarounds, and compliance impact

Interactive AI chat

Ask questions about this vulnerability in natural language

Related vulnerabilities

Semantically similar CVEs and attack patterns

REST API & MCP access

Integrate vulnerability data into your workflows