Authorization Bypass Through User-Controlled Key Affecting keycloak-advanced-compat package, versions <26.6.3-r0


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

Social Trends
EPSS
0.31% (23rd percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-KEYCLOAKADVANCEDCOMPAT-17329073
  • published13 Jun 2026
  • disclosed20 May 2026

Introduced: 20 May 2026

CVE-2026-9087  (opens in a new tab)
CWE-639  (opens in a new tab)

How to fix?

Upgrade Minimos:latest keycloak-advanced-compat to version 26.6.3-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream keycloak-advanced-compat package and not the keycloak-advanced-compat package as distributed by Minimos. See How to fix? for Minimos:latest relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1