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Keycloak LDAP User Federation provider enables admin-triggered untrusted Java deserialization

Moderate severity GitHub Reviewed Published Dec 19, 2025 in keycloak/keycloak • Updated Dec 19, 2025

Package

maven org.keycloak:keycloak-ldap-federation (Maven)

Affected versions

< 26.4.6

Patched versions

26.4.6

Description

A flaw was found in the Keycloak LDAP User Federation provider. This vulnerability allows an authenticated realm administrator to trigger deserialization of untrusted Java objects via a malicious LDAP server configuration.

Mitigation

Disable LDAP referrals in all LDAP user providers in all realms if projects cannot upgrade to the patched versions.

References

@rmartinc rmartinc published to keycloak/keycloak Dec 19, 2025
Published to the GitHub Advisory Database Dec 19, 2025
Reviewed Dec 19, 2025
Last updated Dec 19, 2025

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(4th percentile)

Weaknesses

Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. Learn more on MITRE.

CVE ID

CVE-2025-13467

GHSA ID

GHSA-4hx9-48xh-5mxr

Source code

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