CVE-2026-9087

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

Published: May 20, 2026Updated: Jul 23, 2026 Sources: CVE List NVDCWE-639

6.4MEDIUM

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:HAttack Complexity

High

PR:LPrivileges Required

Low

UI:RUser Interaction

Required

Scope

S:UScope

Unchanged

Impact

C:HConfidentiality

High

I:HIntegrity

High

A:NAvailability

None

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Weaknesses

CWE-639

Affected Products

Red Hat

commercial·USaka redhat

Red Hat build of Keycloak 26.4On-premWeb App

Web & CMS Plugins

Red Hat build of Keycloak 26.4.13On-prem

DevTools & CI

Red Hat build of Keycloak 26.6On-prem

Security Products / identity-access-mgmt

Red Hat build of Keycloak 26.6.3On-prem

Security Products / identity-access-mgmt

build of keycloakOn-prem

Operating Systems / linux-distro

Exploitability

Official Patch Available

Workaround Available

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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique

Initial Access

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References

https://access.redhat.com/errata/RHSA-2026:25097

access.redhat.com

https://access.redhat.com/errata/RHSA-2026:25098

access.redhat.com

https://access.redhat.com/errata/RHSA-2026:30049

access.redhat.com

and 3 more references View all →

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