CVE-2026-9801: Keycloak Vulnerable to Improper Validation of Specified Quantity in Input
(updated )
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.
References
- access.redhat.com/errata/RHSA-2026:25097
- access.redhat.com/errata/RHSA-2026:25098
- access.redhat.com/errata/RHSA-2026:30049
- access.redhat.com/errata/RHSA-2026:30050
- access.redhat.com/security/cve/CVE-2026-9801
- bugzilla.redhat.com/show_bug.cgi?id=2482473
- github.com/advisories/GHSA-f6r7-6w34-x2gp
- github.com/keycloak/keycloak/commit/2c4fe42235ba8c265b1da3a30541a270d5bd8c39
- github.com/keycloak/keycloak/issues/49434
- github.com/keycloak/keycloak/pull/49514
- nvd.nist.gov/vuln/detail/CVE-2026-9801
Code Behaviors & Features
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