Maxi Blocks <= 2.1.9 - Authenticated (Author+) Stored Cross-Site Scripting via Style Card REST API

{
  "id": "1aba9d3b4e14c8494b2728532b76e80df74845f651e6e1db2a8481d5443a57f5",
  "url": "https://osv.dev/vulnerability/CVE-2026-6378",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Maxi Blocks <= 2.1.9 - Authenticated (Author+) Stored Cross-Site Scripting via Style Card REST API",
    "summary": "The Maxi Blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `/wp-json/maxi-blocks/v1.0/style-card` REST API endpoint in all versions up to, and including, 2.1.9 due to insufficient input sanitization and output escaping of the `sc_styles` parameter. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts that execute on every page where the plugin's style card styles are loaded, including across the entire WordPress admin panel.",
    "evidence": "osv:CVE-2026-6378",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-6378",
      "aliases": [
        "CVE-2026-6378"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/maxi-blocks/maxi-blocks",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "c95407298f09c94a85bada86127db5ab0a30d26f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "2.1.9"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.1.9",
            "v2.1.8",
            "v2.1.7",
            "v2.1.6",
            "v2.1.4",
            "v2.1.2",
            "v2.0.9",
            "v2.1.0",
            "v2.0.7",
            "v2.0.6",
            "v2.0.5",
            "v2.0.4",
            "v2.0.3",
            "v2.0.1",
            "v2.0.0",
            "v1.9.9",
            "v1.9.8",
            "v1.9.7",
            "v1.9.2",
            "v1.9.1",
            "v1.9.0",
            "v1.8.9",
            "v1.8.8",
            "v1.8.5",
            "v1.8.4",
            "v1.8.3",
            "v1.8.2",
            "v1.8.1",
            "1.8.0",
            "v1.7.3",
            "v1.7.2",
            "v1.7.1",
            "v1.7.0",
            "v.1.6.1",
            "v1.6.0",
            "v1.5.8",
            "v1.5.7",
            "v1.5.6",
            "v1.5.5",
            "v1.5.3",
            "v1.5.2",
            "v1.5.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-6378.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.053980911Z",
      "provider": "osv",
      "references": [
        "https://github.com/maxi-blocks/maxi-blocks/pull/6250/changes/8db3267df9858f684e420566227ed2ea7954d9a9",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.10/core/class-maxi-api.php#L1010",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.10/core/class-maxi-api.php#L1021",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.10/core/class-maxi-api.php#L979",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.10/core/class-maxi-api.php#L981",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.10/core/class-maxi-api.php#L987",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.9/core/class-maxi-api.php#L221",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.9/core/class-maxi-api.php#L979",
        "https://plugins.trac.wordpress.org/browser/maxi-blocks/tags/2.1.9/core/class-maxi-style-cards.php#L197",
        "https://www.wordfence.com/threat-intel/vulnerabilities/id/22f05048-df38-4f26-82a3-53caac995283?source=cve",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6378.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-6378"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "cna_assigner": "Wordfence",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6378.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-6378",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519855,
  "published_at": "2026-05-02T03:36:42.285+00:00"
}