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Vulnerability from bitnami_vulndb
Published
2026-08-25 11:42
Modified
2026-09-08 08:34
Summary
Keycloak: keycloak: cross-site scripting (xss) via case-insensitive uri validation bypass
Details

A flaw was found in Keycloak. A remote attacker with administrative privileges, specifically those with manage-client permission or access to client registration endpoints, could bypass client Uniform Resource Identifier (URI) validation. This is achieved by registering a malicious client with a specially crafted redirect URI using a case-insensitive javascript: or data: scheme. This Cross-Site Scripting (XSS) vulnerability allows for arbitrary code execution in the Keycloak origin when a victim clicks the crafted link, such as in the logout flow or the Admin Console.

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "keycloak",
        "purl": "pkg:bitnami/keycloak"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "26.4.0"
            },
            {
              "fixed": "26.4.13"
            },
            {
              "introduced": "26.6.0"
            },
            {
              "fixed": "26.6.4"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-9086"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*",
      "cpe:2.3:a:keycloak:keycloak:*:*:*:*:*:*:*:*"
    ],
    "severity": "High"
  },
  "details": "A flaw was found in Keycloak. A remote attacker with administrative privileges, specifically those with `manage-client` permission or access to client registration endpoints, could bypass client Uniform Resource Identifier (URI) validation. This is achieved by registering a malicious client with a specially crafted redirect URI using a case-insensitive `javascript:` or `data:` scheme. This Cross-Site Scripting (XSS) vulnerability allows for arbitrary code execution in the Keycloak origin when a victim clicks the crafted link, such as in the logout flow or the Admin Console.",
  "id": "BIT-keycloak-2026-9086",
  "modified": "2026-09-08T08:34:36.952Z",
  "published": "2026-08-25T11:42:40.305Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30049"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30050"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30083"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:30084"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-9086"
    },
    {
      "type": "ADVISORY",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2480170"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9086"
    },
    {
      "type": "ADVISORY",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9086.json"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Keycloak: keycloak: cross-site scripting (xss) via case-insensitive uri validation bypass"
}



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