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Full vulnerability report · 2025
CVE-2025-11419High confidence

Keycloak: keycloak tls client-initiated renegotiation denial of service

Unknown · Unknown

Official source article: Red Hat RHSA-2025:18254 ↗. Check the applicable product and release in the original source.

7.5HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.71% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Unknown Unknown and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Open-source package ranges3 source-attributed ranges

These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.

Ecosystem and packageAffected rangeFirst fixed versionEvidence
mavenorg.keycloak:keycloak-quarkus-dist< 26.0.1626.0.16GitHub advisory ↗upstream repository advisory · 24 Apr 2026
mavenorg.keycloak:keycloak-quarkus-dist>= 26.1.0, < 26.2.1026.2.10GitHub advisory ↗upstream repository advisory · 24 Apr 2026
mavenorg.keycloak:keycloak-quarkus-dist>= 26.3.0, < 26.4.126.4.1GitHub advisory ↗upstream repository advisory · 24 Apr 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2025-11419 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitykeycloak: Keycloak TLS Client-Initiated Renegotiation Denial of Service
18 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • rhbk/keycloak-operator-bundle@sha256:43a298583415c35ecbb5325283a9892566bd08fb0eb2ebd37e90610d88269649_amd64 as a component of Red Hat build of Keycloak 26.0
  • rhbk/keycloak-rhel9-operator@sha256:14b0fbc122f85168376a1769d591641fc2c8e93c0d0b771065cd3779b5ebc546_amd64 as a component of Red Hat build of Keycloak 26.0
  • rhbk/keycloak-rhel9-operator@sha256:3df0789cf7012777396528a72fd7c8af718bdf61e79ca3a5097ee77e37ade59d_ppc64le as a component of Red Hat build of Keycloak 26.0
  • rhbk/keycloak-rhel9-operator@sha256:aef5994b152d534e81c9832b67cf6ff68e760d55915f830be02ac2bcaceae553_s390x as a component of Red Hat build of Keycloak 26.0
  • rhbk/keycloak-rhel9@sha256:42c1e459585e03df56aca5bbf83081d95f21b121f623fec4d36e9a42f697f945_s390x as a component of Red Hat build of Keycloak 26.0
  • rhbk/keycloak-rhel9@sha256:bbda28678bec5d9778a3f0da5bb2cb9becc971f6080eb03758316721720b83e8_amd64 as a component of Red Hat build of Keycloak 26.0
  • rhbk/keycloak-rhel9@sha256:cfc457ab3d6cadd50622b18a1bf3967754545ba3cc435cd29ad4e80d592050e5_ppc64le as a component of Red Hat build of Keycloak 26.0
  • rhbk/keycloak-operator-bundle@sha256:4799ddae8374f34fb57fa7a27f5248f02420b808ef1c62042fa4315cc88f0dfb_amd64 as a component of Red Hat build of Keycloak 26.2
  • rhbk/keycloak-rhel9-operator@sha256:087a5a887392ed14b858d87b92fe46abb5c49c8bae96fe78abcf0767fd20f0ed_s390x as a component of Red Hat build of Keycloak 26.2
  • rhbk/keycloak-rhel9-operator@sha256:3ea74e7e42176115fcda6831ab8c70ab21975b42b5d0d3f8e60114396e992420_ppc64le as a component of Red Hat build of Keycloak 26.2
  • rhbk/keycloak-rhel9-operator@sha256:95132189f2539f5c80beb8293acfe858e62cebdc1824aa86d54f56a9183d5469_arm64 as a component of Red Hat build of Keycloak 26.2
  • rhbk/keycloak-rhel9-operator@sha256:9d0f6631fb91d3c4019b8cb724ecb3c23f8ea37224b1878cb83df9b855ce469f_amd64 as a component of Red Hat build of Keycloak 26.2
Summary
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.
Remediation
Before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2025-36356

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

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.

Why

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Allocation of Resources Without Limits or Throttling → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-770 ↗

CWE-770: Allocation of Resources Without Limits or Throttling. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-770
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2025-2224Keycloak: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Keycloak ausnutzen, um einen Denial of Service Angriff durchzuführen und Sicherheitsmaßnahmen zu umgehen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20251224Security Bulletin 24 Dec 2025

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 24 Dec 2025, published on 24 December 2025. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
< 26.0.16, 26.1.0 < 26.1.*, 26.2.0 < 26.2.10, 26.3.0 < 26.3.*, 26.4.0 < 26.4.1
Fixed
Action
Before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 23 Dec 2025 · Last source change 20 Apr 2026, 17:45 UTC · CWE-770 · Allocation of Resources Without Limits or Throttling

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2025-36356
Product sourceUnavailable
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD not scheduled

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2025-36356↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference · Red Hat RHSA-2025:18254↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2025-11419 · cve.blacktree.nl