CVE-2026-9801: Keycloak ldap federation Keycloak Vulnerable To Improper Validation Vulnerability
MODERATECVE-2026-9801 is a MODERATE (CVSS 4.9) keycloak vulnerable to improper validation vulnerability (CWE-1284: Improper Validation of Specified Quantity in Input) affecting Keycloak ldap federation libraries in the Maven ecosystem. The issue involves keycloak vulnerable to improper validation of specified quantity in input. Remediation is available by upgrading affected packages to version 26.6.3.
CVE-2026-9801 at a Glance
Security Impact
CVSS: 4.9
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
How to Fix CVE-2026-9801
To remediate this vulnerability, upgrade all affected Keycloak ldap federation dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
<dependency>
<groupId>org.keycloak</groupId>
<artifactId>keycloak-ldap-federation</artifactId>
<version>26.6.3</version>
</dependency>Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=org.keycloakHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-9801, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=org.keycloakAnalyze the terminal output to locate any version of Keycloak ldap federation in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 26.6.3), your application is affected.
Note: The mvn dependency:tree -Dincludes=org.keycloak command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-1284: Improper Validation of Specified Quantity in Input, where the product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties. In Keycloak ldap federation, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-9801 Affected Keycloak ldap federation Versions
1 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
org.keycloak:keycloak-ldap-federation
|
Maven |
< 26.6.3
|
26.6.3
|
References
Frequently Asked Questions
What is CVE-2026-9801?
Which Keycloak ldap federation versions are affected?
What version fixes CVE-2026-9801?
Is keycloak-ldap-federation affected?
What is the CVSS score of CVE-2026-9801?
What CWE is associated with CVE-2026-9801?
How can I check Maven dependencies for CVE-2026-9801?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-f6r7-6w34-x2gp",
"modified" : "2026-07-01T21:26:37Z",
"published" : "2026-05-28T06:31:10Z",
"aliases" : [ "CVE-2026-9801" ],
"summary" : "Keycloak Vulnerable to Improper Validation of Specified Quantity in Input",
"details" : "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.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "org.keycloak:keycloak-ldap-federation"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "26.6.3"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-9801"
}, {
"type" : "WEB",
"url" : "https://github.com/keycloak/keycloak/issues/49434"
}, {
"type" : "WEB",
"url" : "https://github.com/keycloak/keycloak/pull/49514"
}, {
"type" : "WEB",
"url" : "https://github.com/keycloak/keycloak/commit/2c4fe42235ba8c265b1da3a30541a270d5bd8c39"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:25097"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:25098"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:30049"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:30050"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/security/cve/CVE-2026-9801"
}, {
"type" : "WEB",
"url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2482473"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/keycloak/keycloak"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-1284" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-07-01T21:26:37Z",
"nvd_published_at" : "2026-05-28T06:16:29Z"
}
}