{"id":"CVE-2026-18203","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-18203","generatedAt":"2026-10-28T10:46:04.073Z","title":"This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.","description":"A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check to verify group membership. This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.","published":"2026-07-31T08:16:27.000Z","lastModified":"2026-08-07T14:56:33.000Z","status":"Analyzed","sourceIdentifier":"secalert@redhat.com","cvss":{"version":"3.1","score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"},"cwe":["CWE-863"],"affected":["redhat/build of keycloak"],"epss":{"score":0.00312,"percentile":0.23953,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-18203","tags":["Vendor Advisory"],"source":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2508291","tags":["Issue Tracking","Vendor Advisory"],"source":"secalert@redhat.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-18203","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}