Improper Validation of Specified Quantity in Input Affecting keycloak-advanced-compat package, versions <26.6.3-r0


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.32% (24th percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-KEYCLOAKADVANCEDCOMPAT-17804530
  • published3 Jul 2026
  • disclosed27 May 2026

Introduced: 27 May 2026

CVE-2026-9704  (opens in a new tab)
CWE-1284  (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. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subject_token JSON Web Token (JWT) to the TokenEndpoint. When the token exceeds a 4000-character limit, it is silently dropped, causing the system to fall back to client credentials. This allows the user to gain the permissions of the client's service account, leading to privilege escalation.

CVSS Base Scores

version 3.1