Keycloak: keycloak tls client-initiated renegotiation denial of service
Summary
| CVE | CVE-2025-11419 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2025-12-23 21:15:46 UTC |
| Updated | 2026-04-20 18:16:22 UTC |
| Description | A flaw was found in Keycloak. This vulnerability allows an unauthenticated remote attacker to cause a denial of service (DoS) by repeatedly initiating TLS 1.2 client-initiated renegotiation requests to exhaust server CPU resources, making the service unavailable. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.000460000 probability, percentile 0.142470000 (date 2026-04-21)
Problem Types: CWE-770 | CWE-770 Allocation of Resources Without Limits or Throttling
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Build Of Keycloak 26.0 | unaffected 26.0.16-2 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.0 | unaffected 26.0-20 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.0 | unaffected 26.0-21 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.0.16 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2 | unaffected 26.2.10-2 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2 | unaffected 26.2-11 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2 | unaffected 26.2-11 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.2.10 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/security/cve/CVE-2025-11419 | [email protected] | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/errata/RHSA-2025:18890 | [email protected] | access.redhat.com | |
| github.com/keycloak/keycloak/issues/43020 | [email protected] | github.com | |
| github.com/keycloak/keycloak/discussions/25209 | [email protected] | github.com | |
| access.redhat.com/errata/RHSA-2025:18254 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2025:18889 | [email protected] | access.redhat.com | |
| access.redhat.com/errata/RHSA-2025:18255 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2025-10-07T11:12:36.431Z | Reported to Red Hat. |
| CNA | 2025-10-07T00:00:00.000Z | Made public. |
Workarounds
CNA: To mitigate this vulnerability, configure Keycloak to reject client-initiated TLS renegotiation by adding the following Java system property to the Keycloak startup configuration: -Djdk.tls.rejectClientInitiatedRenegotiation=true This prevents unauthenticated attackers from triggering repeated TLS renegotiations and exhausting server CPU resources. Additionally, ensure that Keycloak is deployed behind proper network access controls and rate-limiting mechanisms to further reduce exposure to DoS attacks.