{"id":"CVE-2026-0976","aliases":["EUVD-2026-2822","GHSA-v897-pv23-r8cw"],"status":"published","title":"Org.keycloak/keycloak-quarkus-server: keycloak: proxy bypass due to improper handling of matrix parameters in url paths","description":"A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.","severity":{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00489,"percentile":0.42444,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-20"],"published":"2026-01-15T12:06:21Z","modified":"2026-10-23T00:45:08Z","affected":[{"source":"ghsa","ecosystem":"Maven","package":"org.keycloak:keycloak-quarkus-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"26.2.5"}]}]},{"source":"osv","ecosystem":"Maven","package":"org.keycloak:keycloak-quarkus-server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"26.2.5"}]}],"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"]}],"products":[{"vendor":"red hat","product":"red hat build of keycloak"},{"vendor":"red hat","product":"red hat build of keycloak 26.4.9"},{"vendor":"red hat","product":"red hat jboss enterprise application platform 8"},{"vendor":"red hat","product":"red hat jboss enterprise application platform expansion pack"}],"references":[{"url":"https://access.redhat.com/errata/RHSA-2026:2365","tags":["vendor-advisory","x_refsource_REDHAT","web"]},{"url":"https://access.redhat.com/security/cve/CVE-2026-0976","tags":["vdb-entry","x_refsource_REDHAT","web"]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2429869","tags":["issue-tracking","x_refsource_REDHAT","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-0976","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-v897-pv23-r8cw"},{"url":"https://github.com/keycloak/keycloak","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-0976","title":"Org.keycloak/keycloak-quarkus-server: keycloak: proxy bypass due to improper handling of matrix parameters in url paths","description":"A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.","status":"published","published":"2026-01-15T12:06:21.251Z","modified":"2026-10-22T21:17:19.726Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:20:13.587351Z"}],"euvd":[{"id":"EUVD-2026-2822","description":"A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.","status":"published","published":"2026-01-15T12:06:21Z","modified":"2026-10-22T21:17:19Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T16:59:34.021826Z"}],"ghsa":[{"id":"GHSA-v897-pv23-r8cw","title":"Keycloak has an improper input validation vulnerability","description":"A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.","status":"published","published":"2026-01-15T15:31:17Z","modified":"2026-10-23T00:32:50Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:41:35.723785Z"}],"nvd":[{"id":"CVE-2026-0976","description":"A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.","status":"published","published":"2026-01-15T13:16:04.91Z","modified":"2026-10-22T22:17:41.857Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:12:04.066712Z"}],"osv":[{"id":"GHSA-v897-pv23-r8cw","title":"Keycloak has an improper input validation vulnerability","description":"A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.","status":"published","published":"2026-01-15T15:31:17Z","modified":"2026-10-23T00:45:08.188819869Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T15:46:56.981655Z"}]}}