CVE-2026-117859

Keycloak-services: keycloak-services: par single-use bypass via flow restart

Published Oct 29, 2026 CVSS 3.1 · 5.4 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in the Pushed Authorization Request PAR implementation of the keycloak-services component. The issue occurs when an authentication flow is restarted, which incorrectly clears the internal markers used to track PAR consumption while leaving the request active. This allows an attacker to reuse the same authorization request to obtain multiple access tokens, bypassing security requirements for single-use requests.

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

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

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

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
Type Values Removed Values Added
Description A flaw was found in the Pushed Authorization Request PAR implementation of the keycloak-services component. The issue occurs when an authentication flow is restarted, which incorrectly clears the internal markers used to track PAR consumption while leaving the request active. This allows an attacker to reuse the same authorization request to obtain multiple access tokens, bypassing security requirements for single-use requests.
Title Keycloak-services: keycloak-services: par single-use bypass via flow restart
First Time appeared Redhat
Redhat build Keycloak
Redhat red Hat Single Sign On
Weaknesses CWE-670
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': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Oct 29, 2026, 5:20 PM
Reserved
Oct 27, 2026, 2:02 PM
Status
Awaiting Analysis
Published
Oct 29, 2026, 7:16 AM
Modified
Oct 29, 2026, 6:17 PM
Severity
Moderate
Public date
Oct 26, 2026, 6:19 PM