---
id: "CVE-2026-117691"
kind: "vulnerability"
aliases: ["CVE-2026-117691"]
title: "Keycloak: SAML broker redirect login accepts a forged response under a percent-encoded parameter name, allowing account takeover; no fixed version yet"
severity: "critical"
cvss: 9.1
epss: null
exploited: false
status: "open"
category: "runtime"
products: [{"name": "keycloak", "fixed": [], "affected": "26.8.1 confirmed; earlier releases likely (26.7.5 same code per secondary source)", "ecosystem": "vendor"}, {"name": "Red Hat Build of Keycloak", "fixed": [], "affected": "listed as affected, versions not stated", "ecosystem": "vendor"}]
ecosystems: []
tags: ["keycloak", "red-hat-build-of-keycloak", "runtime", "saml", "self-hosted", "sso"]
not_affected_if: ["no-saml", "oidc-only", "post-binding-only", "want-assertions-signed"]
published_at: "2026-11-05T14:17:01+00:00"
first_seen_at: "2026-11-05T14:39:17+00:00"
updated_at: "2026-11-05T14:41:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117691", "first_seen_at": "2026-11-05T14:39:17+00:00"}, {"source": "analyst", "url": "https://access.redhat.com/security/cve/CVE-2026-117691", "first_seen_at": "2026-11-05T14:41:45+00:00", "cites": ["https://access.redhat.com/security/cve/CVE-2026-117691", "https://github.com/keycloak/keycloak/issues/53354", "https://abraxaslabs.tech/research/keycloak-saml-redirect-param-split"]}]
exploit_sources: [{"type": "poc", "url": "https://abraxaslabs.tech/research/keycloak-saml-redirect-param-split"}]
---

# Keycloak: SAML broker redirect login accepts a forged response under a percent-encoded parameter name, allowing account takeover; no fixed version yet

Keycloak's SAML broker takes the response from a percent-encoded parameter name (SAML%52esponse) while the signature check reads the raw names, so an attacker with one genuinely signed redirect from the IdP can log in as any user. A public PoC exists for 26.8.1; no fix is published.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:keycloak affected 26.8.1 confirmed; earlier releases likely (26.7.5 same code per secondary source) fixed no fixed version listed
- vendor:Red Hat Build of Keycloak affected listed as affected, versions not stated fixed no fixed version listed

## How to check

- Version: kc.sh --version or the image tag. 26.8.1 is confirmed vulnerable by the researcher; 26.7.5 has the same code shape per a secondary analysis, so treat all current releases as exposed.
- Admin console > Identity providers: you are exposed if a SAML provider has 'Validate Signatures' on, 'Want Assertions Signed' off, and the IdP signs HTTP-Redirect responses (SigAlg and Signature in the query string).
- Not exposed: no SAML brokering, OIDC only, or an IdP that only uses HTTP-POST.
- Also check if you use Red Hat Build of Keycloak; Red Hat lists it as affected.

## Fix

No fixed version published as of 2026-11-05. Red Hat's page lists none and says no mitigation is available. Keycloak 26.8.1 (13 Oct 2026) fixes the related semicolon variant (#53354) but a researcher reproduced this one on 26.8.1. Watch https://github.com/keycloak/keycloak/releases. Until then, set 'Want Assertions Signed' on every SAML identity provider that signs HTTP-Redirect responses (the researcher says this blocks it; the setting is off by default after metadata import) — not confirmed by the vendor.

## Timeline

- 2026-11-05T14:39:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117691
- 2026-11-05T14:41:45+00:00 analyst https://access.redhat.com/security/cve/CVE-2026-117691 — Red Hat CVE page (CNA, reporter Mayssen Aidoudi) gives no versions or fix. Public PoC from Abraxas Labs reproduces percent-encoded name split on 26.8.1 with preconditions (signature validation on, wantAssertionsSigned off, IdP signs redirect). Distinct from #53354 (semicolon, fixed in 26.8.1). No in-the-wild exploitation seen. Researcher rated 7.4 (AC:H), Red Hat 9.1; severity left. Nothing marked verified: no vendor fixed-version statement. Note: researcher's page does not cite this CVE id; mapping is by matching description.

## Documents

- [advisory] Red Hat: CVE-2026-117691 https://access.redhat.com/security/cve/CVE-2026-117691
- [mentions] Keycloak #53354: SAML broker redirect ';' separator (sibling, fixed in 26.8.1) https://github.com/keycloak/keycloak/issues/53354
- [poc] Abraxas Labs: Keycloak 26.8.1, SAML redirect query-name split https://abraxaslabs.tech/research/keycloak-saml-redirect-param-split

## From the sources

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.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_