Improper Validation of Specified Quantity in Input Affecting org.keycloak:keycloak-services package, versions [,26.6.3)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-ORGKEYCLOAK-17139471
- published3 Jun 2026
- disclosed27 May 2026
- creditFilip Jovanov
Introduced: 27 May 2026
CVE-2026-9704 (opens in a new tab)How to fix?
Upgrade org.keycloak:keycloak-services to version 26.6.3 or higher.
Overview
org.keycloak:keycloak-services is an open source identity and access management solution for modern applications and services.
Affected versions of this package are vulnerable to Improper Validation of Specified Quantity in Input in the TokenEndpoint endpoint when an oversized subject_token JWT exceeding 4000 characters is submitted. An attacker can gain unintended service account permissions by exploiting the fallback to client credentials that occurs when the oversized token is silently dropped.
Workaround
This vulnerability can be mitigated by configuring strict parameter validation, specifically by setting the fail-fast parameter to true for the TokenEndpoint configuration, which will explicitly reject requests with oversized parameters.