{"id":"CVE-2024-9666","aliases":["EUVD-2024-3365","GHSA-jgwc-jh89-rpgq"],"status":"published","title":"Org.keycloak/keycloak-quarkus-server: keycloak proxy header handling denial-of-service (dos) vulnerability","description":"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 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.","severity":{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00403,"percentile":0.34794,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-444"],"published":"2024-11-25T07:29:52Z","modified":"2026-11-04T02:31:00Z","fixes":[{"ecosystem":"Maven","package":"org.keycloak:keycloak-quarkus-server","fixed_in":["24.0.9","26.0.6"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Maven","package":"org.keycloak:keycloak-quarkus-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"24.0.9"}]}]},{"source":"ghsa","ecosystem":"Maven","package":"org.keycloak:keycloak-quarkus-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"25.0.0"},{"fixed":"26.0.6"}]}]},{"source":"osv","ecosystem":"Maven","package":"org.keycloak:keycloak-quarkus-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["12.0.0","12.0.1","12.0.2","12.0.3","12.0.4","13.0.0","13.0.1","14.0.0","15.0.0","15.0.1","15.0.2","15.1.0","15.1.1","16.0.0","16.1.0","16.1.1","17.0.0","17.0.1","18.0.0","18.0.1","18.0.2","19.0.0","19.0.1","19.0.2","19.0.3","20.0.0","20.0.1","20.0.2","20.0.3","20.0.4","20.0.5","21.0.0","21.0.1","21.0.2","21.1.0","21.1.1","21.1.2","22.0.0","22.0.1","22.0.2","22.0.3","22.0.4","22.0.5","23.0.0","23.0.1","23.0.2","23.0.3","23.0.4","23.0.5","23.0.6","23.0.7","24.0.0","24.0.1","24.0.2","24.0.3","24.0.4","24.0.5","25.0.0","25.0.1","25.0.2","25.0.3","25.0.4","25.0.5","25.0.6","26.0.0","26.0.1","26.0.2","26.0.4","26.0.5","26.0.6","26.0.7","26.0.8","26.1.0","26.1.1","26.1.2","26.1.3","26.1.4","26.1.5","26.2.0","26.2.1","26.2.2","26.2.3","26.2.4","26.2.5","26.3.0","26.3.1","26.3.2","26.3.3","26.3.4","26.3.5","26.4.0","26.4.1","26.4.2","26.4.3","26.4.4","26.4.5","26.4.6","26.4.7","26.5.0","26.5.1","26.5.2","26.5.3","26.5.4","26.5.5","26.5.6","26.5.7","26.6.0","26.6.1","26.6.2","26.6.3","26.6.4","26.7.0","26.7.1","26.7.2","26.7.3"]},{"source":"osv","ecosystem":"Maven","package":"org.keycloak:keycloak-quarkus-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"25.0.0"},{"fixed":"26.0.6"}]}],"versions":["25.0.0","25.0.1","25.0.2","25.0.3","25.0.4","25.0.5","25.0.6","26.0.0","26.0.1","26.0.2","26.0.4","26.0.5"]}],"products":[{"vendor":"red hat","product":"red hat build of keycloak"},{"vendor":"red hat","product":"red hat build of keycloak 24"},{"vendor":"red hat","product":"red hat build of keycloak 24.0.9"},{"vendor":"red hat","product":"red hat build of keycloak 26.0"},{"vendor":"red hat","product":"red hat build of keycloak 26.0.6"},{"vendor":"red hat","product":"red hat jboss enterprise application platform 8"}],"references":[{"url":"https://access.redhat.com/errata/RHSA-2024:10175","tags":["vendor-advisory","x_refsource_REDHAT","advisory","web"]},{"url":"https://access.redhat.com/errata/RHSA-2024:10176","tags":["vendor-advisory","x_refsource_REDHAT","advisory","web"]},{"url":"https://access.redhat.com/errata/RHSA-2024:10177","tags":["vendor-advisory","x_refsource_REDHAT","advisory","web"]},{"url":"https://access.redhat.com/errata/RHSA-2024:10178","tags":["vendor-advisory","x_refsource_REDHAT","advisory","web"]},{"url":"https://access.redhat.com/security/cve/CVE-2024-9666","tags":["vdb-entry","x_refsource_REDHAT","advisory","web"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2317440","tags":["issue-tracking","x_refsource_REDHAT","report","web"]},{"url":"https://github.com/keycloak/keycloak/security/advisories/GHSA-jgwc-jh89-rpgq","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-9666","tags":["advisory"]},{"url":"https://github.com/keycloak/keycloak/issues/35216","tags":["web"]},{"url":"https://github.com/advisories/GHSA-jgwc-jh89-rpgq"},{"url":"https://access.redhat.com/downloads/content/package-browser/","tags":["web"]},{"url":"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html","tags":["web"]},{"url":"https://catalog.redhat.com/software/containers/","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/9xxx/CVE-2024-9666.json","tags":["advisory"]},{"url":"https://github.com/keycloak/keycloak","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2024-9666","title":"Org.keycloak/keycloak-quarkus-server: keycloak proxy header handling denial-of-service (dos) vulnerability","description":"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 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.","status":"published","published":"2024-11-25T07:29:52.073Z","modified":"2026-11-03T09:30:56.413Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-444"],"updated_at":"2026-11-03T10:51:17.986908Z"}],"euvd":[{"id":"EUVD-2024-3365","description":"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 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.","status":"published","published":"2024-11-25T07:29:52Z","modified":"2026-11-03T09:30:56Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T11:53:16.175622Z"}],"ghsa":[{"id":"GHSA-jgwc-jh89-rpgq","title":"Keycloak proxy header handling Denial-of-Service (DoS) vulnerability","description":"Keycloak versions 26 and earlier are vulnerable to a denial-of-service (DoS) attack through 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 can lead to costly DNS resolution operations, which an attacker could exploit to tie up IO threads and potentially cause a denial of service.\n\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\nFor Keycloak version 26, for successful exploitation includes: the realm must have SslRequired=EXTERNAL (the default), HTTP must be enabled, the instance must not be using a full hostname URL, access must come from behind a proxy (assuming the proxy overwrites the X-Forwarded-For header), and trusted proxies must not be set or must incorrectly trust the client from which the request is originating.\n\n","status":"published","published":"2024-11-25T19:39:12Z","modified":"2024-11-25T19:39:12Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"},{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T14:38:23.575854Z"}],"nvd":[{"id":"CVE-2024-9666","description":"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 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.","status":"published","published":"2024-11-25T08:15:10.943Z","modified":"2026-09-21T06:16:59.443Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T14:10:38.347238Z"}],"osv":[{"id":"CVE-2024-9666","title":"Org.keycloak/keycloak-quarkus-server: keycloak proxy header handling denial-of-service (dos) vulnerability","description":"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 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.","status":"published","published":"2024-11-25T07:29:52.073Z","modified":"2026-11-04T02:31:00.930485997Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-04T02:54:44.889498Z"},{"id":"GHSA-jgwc-jh89-rpgq","title":"Keycloak proxy header handling Denial-of-Service (DoS) vulnerability","description":"Keycloak versions 26 and earlier are vulnerable to a denial-of-service (DoS) attack through 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 can lead to costly DNS resolution operations, which an attacker could exploit to tie up IO threads and potentially cause a denial of service.\n\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\nFor Keycloak version 26, for successful exploitation includes: the realm must have SslRequired=EXTERNAL (the default), HTTP must be enabled, the instance must not be using a full hostname URL, access must come from behind a proxy (assuming the proxy overwrites the X-Forwarded-For header), and trusted proxies must not be set or must incorrectly trust the client from which the request is originating.\n\n","status":"published","published":"2024-11-25T19:39:12Z","modified":"2026-09-10T03:50:20.93903226Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"},{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-444"],"updated_at":"2026-11-02T15:46:50.336262Z"}]}}