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.
Problem types
Improper Verification of Cryptographic Signature
Product status
Timeline
| 2026-05-28: | Reported to Red Hat. |
| 2026-05-28: | Made public. |
Credits
Red Hat would like to thank Sree Gopinath (sreelim) for reporting this issue.
References
access.redhat.com/security/cve/CVE-2026-9793
bugzilla.redhat.com/show_bug.cgi?id=2482460 (RHBZ#2482460)