CVE-2026-9793

Medium

Description

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.

SeverityMedium

CVSS5.9

Exploit probability—

Product

Redhat Build Of Keycloak

PublishedMay 28, 2026

First seenMay 28, 2026

Weakness typeCWE-347CWE-347

How to fix

Vendor advisories

Affected products

Product	Affected versions	Fixed in
redhat build_of_keycloak	No range specified	—
org.keycloak:keycloak-servicesMaven	v ≤ 26.6.4	—

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