Description
A flaw was found in the Pushed Authorization Request PAR implementation of Keycloak. The issue occurs when the silent authentication path prompt=none is used, which allows the authorization process to skip certain steps if a user is already logged in. Due to this bypass, the security rule that ensures a pushed request URI is used only once is not enforced. An attacker could potentially reuse a request URI to obtain multiple authorization codes for a user who is already signed in, violating security standards like FAPI-2.
Published: 2026-09-23
Score: 4.2 Medium
EPSS: n/a
KEV: No
Impact: Repeated authorization code issuance
Action: Assess
AI Analysis

Impact

A flaw in Keycloak's Pushed Authorization Request (PAR) handling allows an attacker to bypass the single‑use requirement for the pushed request URI when the silent authentication path (prompt=none) is invoked. This flaw falls under Missing Authorization Control (CWE‑862). The bypass causes the authorization flow to skip steps that normally enforce that a request URI may be used only once. As a result, an attacker who knows or can guess a previously used URI can obtain multiple authorization codes for a user who is already signed in, violating FAPI‑2 security rules.

Affected Systems

Red Hat Build of Keycloak and Red Hat Single Sign‑On 7 are listed as affected products. No specific version ranges are provided in the data, so any deployment of these products that has not been patched or upgraded is at risk. The CPE identifiers indicate the affected applications are the Red Hat Build of Keycloak and the Red Hat Single Sign‑On 7 product bundle.

Risk and Exploitability

The CVSS base score of 4.2 indicates moderate impact, and the EPSS score is not available, so current exploitation likelihood is unknown. The vulnerability is not listed in CISA's KEV catalog, suggesting no widespread known exploitation yet. The likely attack vector is a malicious client that initiates a PAR with prompt=none against a user who is already authenticated; the attacker would then capture multiple authorization codes. No additional prerequisites such as administrator credentials or network access are required beyond the ability to trigger the signed‑in user flow.

Generated by OpenCVE AI on September 23, 2026 at 14:59 UTC.

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.


OpenCVE Recommended Actions

  • Apply the latest Red Hat patch for Keycloak or Single Sign‑On 7 that enforces single‑use of the request URI. If a patch is not yet available, coordinate with Red Hat support for an update.
  • Disable or restrict the silent authentication path (prompt=none) in your Keycloak configuration or enforce stricter session checks for clients that use PAR with prompt=none.
  • Monitor authentication logs for repeated issuance of authorization codes for a single request URI and set alerts for unusual patterns; investigate any suspicious activity promptly.

Generated by OpenCVE AI on September 23, 2026 at 14:59 UTC.

Tracking

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Advisories

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History

Wed, 23 Sep 2026 12:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 23 Sep 2026 11:45:00 +0000

Type Values Removed Values Added
Description A flaw was found in the Pushed Authorization Request PAR implementation of Keycloak. The issue occurs when the silent authentication path prompt=none is used, which allows the authorization process to skip certain steps if a user is already logged in. Due to this bypass, the security rule that ensures a pushed request URI is used only once is not enforced. An attacker could potentially reuse a request URI to obtain multiple authorization codes for a user who is already signed in, violating security standards like FAPI-2.
Title Keycloak-services: keycloak-services: par single-use bypass via prompt=none silent authentication path
First Time appeared Redhat
Redhat build Keycloak
Redhat red Hat Single Sign On
Weaknesses CWE-862
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': 4.2, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N'}


Subscriptions

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

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-09-23T11:03:50.346Z

Reserved: 2026-09-23T09:32:50.973Z

Link: CVE-2026-96446

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-23T12:17:08.913

Modified: 2026-09-23T12:17:08.913

Link: CVE-2026-96446

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-22T14:37:44Z

Links: CVE-2026-96446 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-23T15:00:06Z

Weaknesses