Keycloak has an Improper Verification of Cryptographic Signature issue
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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-9793US | high7.5 | — | ||
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 r… | ||||
references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2026:50846WEB
- https://access.redhat.com/errata/RHSA-2026:50847WEB
- https://access.redhat.com/errata/RHSA-2026:50848WEB
- https://access.redhat.com/errata/RHSA-2026:50849WEB
- https://access.redhat.com/security/cve/CVE-2026-9793WEB
- https://bugzilla.redhat.com/show_bug.cgi?id=2482460WEB
- https://github.com/keycloak/keycloakPACKAGE
- https://github.com/keycloak/keycloak/issues/49429WEB
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