{"cve":"CVE-2026-9087","nvd":{"published":"2026-05-20T17:16:32.207","modified":"2026-07-23T12:10:00.110","status":"Modified","description":"A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId,\nidpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N","score":8.1},"cwes":["CWE-639"],"references":["https://access.redhat.com/errata/RHSA-2026:25097","https://access.redhat.com/errata/RHSA-2026:25098","https://access.redhat.com/errata/RHSA-2026:30049","https://access.redhat.com/errata/RHSA-2026:30050","https://access.redhat.com/security/cve/CVE-2026-9087"],"products":["redhat:build_of_keycloak"],"source":"nvd","synced_at":"2026-10-19T22:35:16.954578616+00:00"},"epss":{"cve":"CVE-2026-9087","score":0.00312,"percentile":0.24067,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-m6qj-3mpp-57v8","url":"https://osv.dev/vulnerability/GHSA-m6qj-3mpp-57v8","summary":"Keycloak: Insufficient verification proof scoping enables identity provider account linking attack and account compromise","modified":"2026-06-26T12:21:29.360806048Z","packages":[{"ecosystem":"Maven","name":"org.keycloak:keycloak-services","purl":"pkg:maven/org.keycloak/keycloak-services","ranges":["<26.6.3"],"fixed":["26.6.3"]}]}],"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."]}