CVE-2026-4634

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Esto conduce a un alto consumo de recursos y tiempos de procesamiento prolongados, lo que finalmente resulta en una denegaci\u00f3n de servicio (DoS) para el servidor Keycloak."}], "id": "CVE-2026-4634", "lastModified": "2026-10-26T21:10:00.170", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "secalert@redhat.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-4634", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-04-03T17:22:51.847497Z", "version": "2.0.3"}}]}, "published": "2026-04-02T13:16:27.027", "references": [{"source": "secalert@redhat.com", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6475"}, {"source": "secalert@redhat.com", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6476"}, {"source": "secalert@redhat.com", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6477"}, {"source": "secalert@redhat.com", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6478"}, {"source": "secalert@redhat.com", "url": "https://access.redhat.com/errata/RHSA-2026:76128"}, {"source": "secalert@redhat.com", "url": "https://access.redhat.com/errata/RHSA-2026:76129"}, {"source": "secalert@redhat.com", "url": "https://access.redhat.com/errata/RHSA-2026:76130"}, {"source": "secalert@redhat.com", "url": "https://access.redhat.com/errata/RHSA-2026:76132"}, {"source": "secalert@redhat.com", "url": "https://access.redhat.com/errata/RHSA-2026:76134"}, {"source": "secalert@redhat.com", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/security/cve/CVE-2026-4634"}, {"source": "secalert@redhat.com", "tags": ["Issue Tracking", "Vendor Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2450250"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6475"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6476"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6477"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/errata/RHSA-2026:6478"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "tags": ["Vendor Advisory"], "url": "https://access.redhat.com/security/cve/CVE-2026-4634"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "tags": ["Issue Tracking", "Vendor Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2450250"}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4634.json"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1050"}], "source": "secalert@redhat.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "CWE-1050"}], "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "type": "Secondary"}]}

{"acknowledgement": "Red Hat would like to thank Slvrqn for reporting this issue.", "affected_release": [{"advisory": "RHSA-2026:6476", "cpe": "cpe:/a:redhat:build_keycloak:26.2::el9", "package": "rhbk/keycloak-operator-bundle:26.2.15-1", "product_name": "Red Hat build of Keycloak 26.2", "release_date": "2026-04-02T00:00:00Z"}, {"advisory": "RHSA-2026:6476", "cpe": "cpe:/a:redhat:build_keycloak:26.2::el9", "package": "rhbk/keycloak-rhel9:26.2-18", "product_name": "Red Hat build of Keycloak 26.2", "release_date": "2026-04-02T00:00:00Z"}, {"advisory": "RHSA-2026:6476", "cpe": "cpe:/a:redhat:build_keycloak:26.2::el9", "package": "rhbk/keycloak-rhel9-operator:26.2-18", "product_name": "Red Hat build of Keycloak 26.2", "release_date": "2026-04-02T00:00:00Z"}, {"advisory": "RHSA-2026:6475", "cpe": "cpe:/a:redhat:build_keycloak:26.2::el9", "package": "rhbk/keycloak-rhel9", "product_name": "Red Hat build of Keycloak 26.2.15", "release_date": "2026-04-02T00:00:00Z"}, {"advisory": "RHSA-2026:6478", "cpe": "cpe:/a:redhat:build_keycloak:26.4::el9", "package": "rhbk/keycloak-operator-bundle:26.4.11-1", "product_name": "Red Hat build of Keycloak 26.4", "release_date": "2026-04-02T00:00:00Z"}, {"advisory": "RHSA-2026:6478", "cpe": "cpe:/a:redhat:build_keycloak:26.4::el9", "package": "rhbk/keycloak-rhel9:26.4-14", "product_name": "Red Hat build of Keycloak 26.4", "release_date": "2026-04-02T00:00:00Z"}, {"advisory": "RHSA-2026:6478", "cpe": "cpe:/a:redhat:build_keycloak:26.4::el9", "package": "rhbk/keycloak-rhel9-operator:26.4-14", "product_name": "Red Hat build of Keycloak 26.4", "release_date": "2026-04-02T00:00:00Z"}, {"advisory": "RHSA-2026:6477", "cpe": "cpe:/a:redhat:build_keycloak:26.4::el9", "package": "rhbk/keycloak-rhel9", "product_name": "Red Hat build of Keycloak 26.4.11", "release_date": "2026-04-02T00:00:00Z"}], "bugzilla": {"description": "keycloak: Keycloak: Denial of Service via excessive processing of OpenID Connect scope parameters", "id": "2450250", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2450250"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "verified"}, "cwe": "CWE-1050", "details": ["A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability."}, "name": "CVE-2026-4634", "public_date": "2026-04-02T12:30:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-4634\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-4634"], "statement": "This is an Important denial of service vulnerability in Red Hat Build of Keycloak (RHBK). An unauthenticated attacker can exploit this flaw by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect token endpoint, leading to high resource consumption and prolonged processing times on the Keycloak server.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": null}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "Red Hat Build of Keycloak", "source": "cna", "vendor": "Red Hat"}, "product": "build_keycloak", "vendor": "redhat"}], "analysis": {"en": {"generated_at": "2026-04-02T23:18:44.894569+00:00", "value": {"mitigation_remediation": ["Apply the latest Red\u00a0Hat Keycloak updates (RHSA\u20112026:6475 through RHSA\u20112026:6478).", "If upgrading is not immediately possible, restrict access to the Keycloak OIDC token endpoint to trusted networks or enforce strict request\u2011size limits as a temporary measure."], "summary": {"action": "Immediate Patch", "impact": "Denial of Service"}, "threat_synthesis": {"affected_systems": "The vulnerability affects Red\u00a0Hat builds of Keycloak 26.2, including the 26.2.15 update, and Red\u00a0Hat builds of Keycloak 26.4, including the 26.4.11 update, all running on Red\u00a0Hat Enterprise Linux 9.", "description_and_impact": "An unauthenticated attacker can send a specially crafted POST request containing an excessively long scope parameter to Keycloak\u2019s OpenID Connect token endpoint. The key server consumes excessive CPU and memory while parsing the parameter, causing prolonged processing times and eventually rendering the service unresponsive. This denial of service can impact all clients relying on the token endpoint for authentication.", "risk_and_exploitability": "The published CVSS score of 7.5 indicates a high severity risk level, while the EPSS score is not available and the issue is not listed in the CISA KEV catalog. Attackers can exploit the flaw remotely from any external network that can reach the exposed token endpoint, without needing authentication. No official workaround exists, making the only effective mitigation the application of vendor patches."}}}}, "created": "2026-04-02T20:12:41.652512+00:00", "updated": "2026-04-03T09:18:47.855890+00:00", "vendors": ["redhat", "redhat$PRODUCT$build_keycloak"]}