CVE-2026-9087

MEDIUM

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

Title source: cna
STIX 2.1

Description

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.

References (6)

Core 6
Core References
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:25097
https://access.redhat.com/errata/RHSA-2026:25097
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:25098
https://access.redhat.com/errata/RHSA-2026:25098
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:30049
https://access.redhat.com/errata/RHSA-2026:30049
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:30050
https://access.redhat.com/errata/RHSA-2026:30050
Vdb Entry, X_Refsource_Redhat vdb-entry x_refsource_redhat
https://access.redhat.com/security/cve/CVE-2026-9087
Issue Tracking, X_Refsource_Redhat issue-tracking x_refsource_redhat
RHBZ#2480172
https://bugzilla.redhat.com/show_bug.cgi?id=2480172

Scores

CVSS v3 6.4
EPSS 0.0031
EPSS Percentile 23.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-639
Status published
Products (12)
org.keycloak/keycloak-services 0 - 26.6.3Maven
Red Hat/Red Hat Build of Keycloak
Red Hat/Red Hat build of Keycloak 26.4 26.4-19
Red Hat/Red Hat build of Keycloak 26.4 26.4.13-1
Red Hat/Red Hat build of Keycloak 26.4.13
Red Hat/Red Hat build of Keycloak 26.6 26.6-6
Red Hat/Red Hat build of Keycloak 26.6 26.6-8
Red Hat/Red Hat build of Keycloak 26.6 26.6.3-3
Red Hat/Red Hat build of Keycloak 26.6 26.6.4-2
Red Hat/Red Hat build of Keycloak 26.6.3
... and 2 more
Published May 20, 2026
Tracked Since May 20, 2026