{"cve":"CVE-2026-4636","nvd":{"published":"2026-04-02T13:16:27.210","modified":"2026-10-26T21:10:00.170","status":"Modified","description":"A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","score":8.1},"cwes":["CWE-551"],"references":["https://access.redhat.com/errata/RHSA-2026:6475","https://access.redhat.com/errata/RHSA-2026:6476","https://access.redhat.com/errata/RHSA-2026:6477","https://access.redhat.com/errata/RHSA-2026:6478","https://access.redhat.com/security/cve/CVE-2026-4636"],"products":["redhat:build_of_keycloak"],"source":"nvd","synced_at":"2026-10-26T21:38:48.864438205+00:00"},"epss":{"cve":"CVE-2026-4636","score":0.00428,"percentile":0.36802,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-f2hx-5fx3-hmcv","url":"https://osv.dev/vulnerability/GHSA-f2hx-5fx3-hmcv","summary":"Keycloak: UMA Policy Resource Injection Allows Unauthorized Cross-User Permission Grants","modified":"2026-09-10T03:50:44.127098993Z","packages":[{"ecosystem":"Maven","name":"org.keycloak:keycloak-services","purl":"pkg:maven/org.keycloak/keycloak-services","ranges":["<26.5.7"],"fixed":["26.5.7"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}