Description
A flaw was found in the SAML HTTP-Redirect binding implementation of Keycloak. The issue occurs because the server processes percent-encoded parameter names (like %53AMLResponse) while the signature verification logic only checks literal parameter names. An attacker can use this discrepancy to provide a crafted, unsigned SAML message that the server processes instead of a legitimately signed one, leading to full account takeover of federated users.
Published: 2026-11-05
Score: 9.1 Critical
EPSS: n/a
KEV: No
AI Analysis

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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

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History

Thu, 05 Nov 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Thu, 05 Nov 2026 17:15:00 +0000

Type Values Removed Values Added
First Time appeared Red Hat
Red Hat red Hat Build Of Keycloak 26.4
Redhat build Of Keycloak
Redhat single Sign-on
Vendors & Products Red Hat
Red Hat red Hat Build Of Keycloak 26.4
Redhat build Of Keycloak
Redhat single Sign-on

Thu, 05 Nov 2026 13:30:00 +0000

Type Values Removed Values Added
Description A flaw was found in the SAML HTTP-Redirect binding implementation of Keycloak. The issue occurs because the server processes percent-encoded parameter names (like %53AMLResponse) while the signature verification logic only checks literal parameter names. An attacker can use this discrepancy to provide a crafted, unsigned SAML message that the server processes instead of a legitimately signed one, leading to full account takeover of federated users.
Title Keycloak-services: keycloak-services: saml redirect binding signature bypass via percent-encoded parameter names
First Time appeared Redhat
Redhat build Keycloak
Redhat red Hat Single Sign On
Weaknesses CWE-347
CPEs cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}


Subscriptions

Red Hat Red Hat Build Of Keycloak 26.4
Redhat Build Keycloak Build Of Keycloak Red Hat Single Sign On Single Sign-on
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-11-05T16:29:19.689Z

Reserved: 2026-10-27T13:49:55.445Z

Link: CVE-2026-117691

cve-icon Vulnrichment

Updated: 2026-11-05T16:28:29.946Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-05T14:17:01.320

Modified: 2026-11-05T17:17:44.750

Link: CVE-2026-117691

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-05T17:00:09Z

Weaknesses
  • CWE-347

    Improper Verification of Cryptographic Signature