---
id: CVE-2026-117691
title: >-
  Keycloak-services: keycloak-services: saml redirect binding signature bypass
  via percent-encoded parameter names
summary: >-
  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…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-347
vendor: Red Hat
product: keycloak-services
affected:
  - keycloak-services (all versions)
  - rhbk/keycloak-rhel9 (all versions)
  - keycloak-services
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-11-05T16:28:53.520705Z'
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T16:29:19.689Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-117691'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-117691'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2561977'
    label: RHBZ#2561977
tags:
  - cve.org
ingestedAt: '2026-11-05T22:38:31.353Z'
---

## Overview

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.

## Affected

- `keycloak-services (all versions)`
- `rhbk/keycloak-rhel9 (all versions)`
- `keycloak-services`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

### Workarounds

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.