CVE-2026-9087 MEDIUM

CVE-2026-9087: Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login

Vendor Red Hat
Product Red Hat build of Keycloak 26.6.3
Weakness CWE-639 · IDOR
Published May 20, 2026
Last update June 10, 2026
View on NVD All CVEs

CVSS base score

6.4/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

What the vulnerability does

01Description

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 and get linked to the victim's local account.

Key dates

02Disclosure timeline

May 20, 2026 CVE published
June 10, 2026 Record updated