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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.4 | — | — |
| Red Hat | Red Hat build of Keycloak 26.4.13 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6 | — | — |
| Red Hat | Red Hat build of Keycloak 26.6.3 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | keycloak-26.5 +2 | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.keycloak:keycloak-ldap-federation | < 26.6.3 | 26.6.3 | GHSA-f6r7-6w34-x2gp |
Advisories 1
- WID-SEC-2026-1708 Keycloak: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
References
- RHSA-2026:25097 vendor-advisory
- RHSA-2026:25098 vendor-advisory
- RHSA-2026:30049 vendor-advisory
- RHSA-2026:30050 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-9801 vdb-entry
- RHBZ#2482473 issue-tracking