Vulnerability in Red Hat Build Of Keycloak
CVE-2026-9801
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.009 (58.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.009 · change: +0.004
Affected products
- Red Hat Build Of Keycloak
- Red Hat Build Of Keycloak 26.4 — versions 26.4.13-1, 26.4-19
- Red Hat Build Of Keycloak 26.4.13
- Red Hat Build Of Keycloak 26.6 — versions 26.6-8, 26.6-6, 26.6.3-3
- Red Hat Build Of Keycloak 26.6.3
- Red Hat Build Of Keycloak 26.6.4
- Red Hat Build Of Keycloak
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-9801 (Mitigation, vdb-entry, Vendor Advisory)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking, Issue Tracking, Vendor Advisory)
- access.redhat.com/errata/RHSA-2026:25098 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:25097 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:30049 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:30050 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-9801?
- CVE-2026-9801 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Improper Validation of Specified Quantity in Input. CVSS score: 4.9/10. Published 2026-05-28.
- How severe is CVE-2026-9801?
- Medium severity. CVSS v3 base score is 4.9 out of 10.