GHSA-F2HX-5FX3-HMCV

Vulnerability from github – Published: 2026-04-02 15:31 – Updated: 2026-04-04 06:00
VLAI
Summary
Keycloak: UMA Policy Resource Injection Allows Unauthorized Cross-User Permission Grants
Details

A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.

Severity
8.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.keycloak:keycloak-services"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "26.5.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-4636"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-551"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-04T06:00:14Z",
    "nvd_published_at": "2026-04-02T13:16:27Z",
    "severity": "HIGH"
  },
  "details": "A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.",
  "id": "GHSA-f2hx-5fx3-hmcv",
  "modified": "2026-04-04T06:00:14Z",
  "published": "2026-04-02T15:31:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4636"
    },
    {
      "type": "WEB",
      "url": "https://github.com/keycloak/keycloak/issues/47717"
    },
    {
      "type": "WEB",
      "url": "https://github.com/keycloak/keycloak/commit/995832f8b74b02833d106c8788bb7a78634aa725"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:6475"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:6476"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:6477"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:6478"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-4636"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2450251"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/keycloak/keycloak"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Keycloak: UMA Policy Resource Injection Allows Unauthorized Cross-User Permission Grants"
}



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