{"id":"CVE-2024-9666","title":"A vulnerability was found in the Keycloak Server","summary":"A vulnerability was found in the Keycloak Server. The Keycloak Server is vulnerable to a denial of service (DoS) attack due to improper handling of proxy headers. When Keycloak is configured to accept incoming proxy headers, it may accep…","severity":"medium","cvss":4.7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-444"],"vendor":"Red Hat","product":"keycloak","affected":["keycloak < 24.0.9","keycloak >= 25.0.0 < 26.0.6","rhbk/keycloak-operator-bundle (all versions)","rhbk/keycloak-rhel9 (all versions)","rhbk/keycloak-rhel9-operator (all versions)","build_of_keycloak_24.0.9","rhbk/keycloak-operator-bundle (all versions)","rhbk/keycloak-rhel9 (all versions)","rhbk/keycloak-rhel9-operator (all versions)","build_of_keycloak_26.0.6","keycloak-quarkus-server (all versions)","keycloak-quarkus-server"],"published":"2024-11-25","updated":"2026-09-21","sourceUpdated":"2026-09-21T06:16:59.443","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2024-9666","references":[{"url":"https://access.redhat.com/errata/RHSA-2024:10175","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:10176","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:10177","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2024:10178","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/security/cve/CVE-2024-9666","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2317440","label":"secalert@redhat.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-9666.json"},{"url":"https://www.cve.org/CVERecord?id=CVE-2024-9666"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-9666"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2024-11-25T17:14:55.721958Z"},"epss":0.00399,"epssPercentile":0.34,"ingestedAt":"2026-08-04T08:38:41.180Z","patched":["build_of_keycloak 24","build_of_keycloak 26.0","build_of_keycloak 24.0.9","build_of_keycloak 26.0.6"],"slug":"CVE-2024-9666","body":"## Overview\n\nA vulnerability was found in the Keycloak Server. The Keycloak Server is vulnerable to a denial of service (DoS) attack due to improper handling of proxy headers. When Keycloak is configured to accept incoming proxy headers, it may accept non-IP values, such as obfuscated identifiers, without proper validation. This issue can lead to costly DNS resolution operations, which an attacker could exploit to tie up IO threads and potentially cause a denial of service.\nThe attacker must have access to send requests to a Keycloak instance that is configured to accept proxy headers, specifically when reverse proxies do not overwrite incoming headers, and Keycloak is configured to trust these headers.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2024:10175** · Red Hat · fixed in: Red Hat build of Keycloak 24 · released 2024-11-21 · [advisory](https://access.redhat.com/errata/RHSA-2024:10175)\n- **RHSA-2024:10177** · Red Hat · fixed in: Red Hat build of Keycloak 26.0 · released 2024-11-21 · [advisory](https://access.redhat.com/errata/RHSA-2024:10177)\n- **RHSA-2024:10176** · Red Hat · fixed in: Red Hat build of Keycloak 24.0.9 · released 2024-11-21 · [advisory](https://access.redhat.com/errata/RHSA-2024:10176)\n- **RHSA-2024:10178** · Red Hat · fixed in: Red Hat build of Keycloak 26.0.6 · released 2024-11-21 · [advisory](https://access.redhat.com/errata/RHSA-2024:10178)\n- **Red Hat VEX** · Low · affected: Red Hat Build of Keycloak · no fix planned: Red Hat Build of Keycloak · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-9666.json)","depth":"sunlit","depthScore":26,"depthScoreParts":{"impact":25.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}