CVE-2026-9793: Red Hat Build Of Keycloak

High severity, CVSS 7.5. EPSS: 0.3% chance of exploitation in the next 30 days.

A flaw was found in Keycloak. When a JSON Web Encryption (JWE) encrypted request object is submitted, Keycloak may incorrectly process unsigned claims if the decrypted content is raw JSON, bypassing the configured signature policy. This allows a remote attacker to submit unauthorized claims, leading to a compromise of data integrity within the OpenID Connect (OIDC) authorization flow. While a redirect URI allowlist acts as a compensating control, this vulnerability violates OIDC Core and Financial-grade API (FAPI) signing requirements.

Affected products

• Red Hat Build Of Keycloak: affected versions not specified

Published 2026-05-28. Last modified 2026-08-20.