CVE-2026-109081

Full vulnerability record from the local CVENow database.

Description

A flaw was found in Keycloak. The Dynamic Client Registration (DCR) endpoint does not properly validate authorization when processing the deprecated defaultRoles field. An authenticated attacker with client creation privileges or an Initial Access Token (IAT) can inject excessive roles into the realm's default roles configuration. This causes clients across the realm to generate bloated access tokens, resulting in performance and memory degradation that can lead to a Denial of Service (DoS).

Severity

MEDIUM

CVSS score

6.8 (v3.1)

Vulnerability status

Awaiting Analysis

Source identifier

[email protected]

Published

2026-11-06 06:16:39.290000

Last modified

2026-11-06 06:16:39.410000

View original CVE JSON

{
  "id": "CVE-2026-109081",
  "sourceIdentifier": "[email protected]",
  "published": "2026-11-06T06:16:39.290",
  "lastModified": "2026-11-06T06:16:39.410",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "A flaw was found in Keycloak. The Dynamic Client Registration (DCR) endpoint does not properly validate authorization when processing the deprecated defaultRoles field. An authenticated attacker with client creation privileges or an Initial Access Token (IAT) can inject excessive roles into the realm's default roles configuration. This causes clients across the realm to generate bloated access tokens, resulting in performance and memory degradation that can lead to a Denial of Service (DoS)."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Red Hat",
          "product": "Red Hat Build of Keycloak",
          "defaultStatus": "affected",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "packageName": "keycloak-services",
          "cpes": [
            "cpe:/a:redhat:build_keycloak:"
          ]
        },
        {
          "vendor": "Red Hat",
          "product": "Red Hat Build of Keycloak",
          "defaultStatus": "affected",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "packageName": "rhbk/keycloak-rhel9",
          "cpes": [
            "cpe:/a:redhat:build_keycloak:"
          ]
        },
        {
          "vendor": "Red Hat",
          "product": "Red Hat Single Sign-On 7",
          "defaultStatus": "unaffected",
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "packageName": "keycloak-services",
          "cpes": [
            "cpe:/a:redhat:red_hat_single_sign_on:7"
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "HIGH",
          "userInteraction": "NONE",
          "scope": "CHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.3,
        "impactScore": 4.0
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-862"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://access.redhat.com/security/cve/CVE-2026-109081",
      "source": "[email protected]"
    }
  ]
}