{"id":"CVE-2026-0976","title":"A flaw was found in Keycloak","summary":"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 re…","severity":"low","cvss":3.7,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","cwe":["CWE-20"],"published":"2026-01-15","updated":"2026-08-09","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-0976","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-0976","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2429869","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/errata/RHSA-2026:2365","label":"RHSA-2026:2365"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-0976"},{"url":"https://github.com/advisories/GHSA-v897-pv23-r8cw"}],"tags":["nvd","cve.org","ghsa","maven"],"epss":0.00489,"epssPercentile":0.41901,"ingestedAt":"2026-08-09T19:34:40.616Z","vendor":"Red Hat","product":"Red Hat build of Keycloak 26.4.9","affected":["build_of_keycloak_26.4.9","keycloak-quarkus-server (all versions)","keycloak-quarkus-server (all versions)","keycloak-quarkus-server-app (all versions)","keycloak-quarkus-server-deployment (all versions)","keycloak-quarkus-server (all versions)","keycloak-quarkus-server-app (all versions)","keycloak-quarkus-server-deployment (all versions)"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-01-15T14:44:09.361820Z"},"aliases":["GHSA-v897-pv23-r8cw"],"ecosystem":"maven","slug":"CVE-2026-0976","body":"## Overview\n\nA 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-0976)\n\nAffected packages:\n\n- `org.keycloak:keycloak-quarkus-server <= 26.2.5`\n\nSource: https://github.com/advisories/GHSA-v897-pv23-r8cw","depth":"sunlit","depthScore":20,"depthScoreParts":{"impact":20.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}