What is CVE-2026-9087?

CVE-2026-9087 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 6.4/10. Published 2026-05-20.

How severe is CVE-2026-9087?

Medium severity. CVSS v3 base score is 6.4 out of 10.

Auth bypass in Red Hat Build Of Keycloak

CVE-2026-9087

A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId, idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it…

Vulnerability class: IDOR (Insecure Direct Object Reference)

EPSS: 0.000 (7.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

CWE-639 — Authorization Bypass Through User-Controlled Key

References

secalert@redhat.com (x_refsource_REDHAT, vdb-entry, Vendor Advisory)
secalert@redhat.com (x_refsource_REDHAT, issue-tracking, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2026-9087?: CVE-2026-9087 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 6.4/10. Published 2026-05-20.
How severe is CVE-2026-9087?: Medium severity. CVSS v3 base score is 6.4 out of 10.