CVE-2026-9793

Keycloak: keycloak: security policy bypass in jwe-encrypted request object processing

Published May 28, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-p3v8-fm5p-v84h Keycloak has an Improper Verification of Cryptographic Signature issue
History
Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
CPEs cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*
Vendors & Products Redhat build Of Keycloak
Type Values Removed Values Added
First Time appeared Redhat keycloak
Vendors & Products Redhat keycloak
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Keycloak: keycloak: security policy bypass in jwe-encrypted request object processing
First Time appeared Redhat
Redhat build Keycloak
Weaknesses CWE-347
CPEs cpe:/a:redhat:build_keycloak:
Vendors & Products Redhat
Redhat build Keycloak
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Aug 20, 2026, 12:54 AM
Reserved
May 28, 2026, 3:11 AM
Status
Modified
Published
May 28, 2026, 5:16 AM
Modified
Oct 26, 2026, 12:10 PM
Severity
Moderate
Public date
May 28, 2026, 3:12 AM