# CVE-2026-117691: Keycloak-services: keycloak-services: saml redirect binding signature bypass via percent-encoded parameter names

Status: published. Published: 2026-11-05. Updated: 2026-11-05.

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.

## Remediation

- 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. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Build of Keycloak (keycloak-services): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Build of Keycloak (rhbk/keycloak-rhel9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Single Sign-On 7 (keycloak-services): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 9.1 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-347

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-117691 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2561977 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-117691; retrieved 2026-11-05; source updated 2026-11-05

Revision: 395d57a8d0234520e43800c9b8b0aac06619351d519ef269a33ecb09e115a93e

Canonical: https://y2.dev/cve/CVE-2026-117691

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