CKEditor: Cross-site scripting (XSS) in the engine package

{
  "id": "bd6ab3d9b8c6cd37bc25fe7572d4980d66e74cd2daf69cb62176c3a47f889d7f",
  "url": "https://osv.dev/vulnerability/GHSA-rh54-vffm-5fvp",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CKEditor: Cross-site scripting (XSS) in the engine package",
    "summary": "### Impact A Cross-Site Scripting (XSS) vulnerability has been discovered in the CKEditor 5 engine. This vulnerability is caused by a prototype pollution issue in the `es-toolkit` library used in the CKEditor 5 codebase. This vulnerability could lead to unauthorized JavaScript code execution when the editor processes incoming `style` attribute values. The underlying issue has been patched by the library maintainers, and the fix has been incorporated into CKEditor 5. ### Patches The problem has been recognized and patched. The fix will be available in version `48.5.1` (and above) and `47.7.4` (LTS). ### For more information Email us at [security@cksource.com](mailto:security@cksource.com) if you have any questions or comments about this advisory.",
    "evidence": "osv:GHSA-rh54-vffm-5fvp",
    "products": [
      {
        "name": {
          "value": "ckeditor5",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "47.7.4",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "@ckeditor/ckeditor5-engine",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "47.7.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "ckeditor5",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "48.5.1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "@ckeditor/ckeditor5-engine",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "48.5.1",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "GHSA-rh54-vffm-5fvp",
      "aliases": [
        "CVE-2026-116688",
        "GHSA-rh54-vffm-5fvp"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "45.0.0"
                },
                {
                  "fixed": "47.7.4"
                }
              ]
            }
          ],
          "package": {
            "name": "ckeditor5",
            "purl": "pkg:npm/ckeditor5",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-rh54-vffm-5fvp/GHSA-rh54-vffm-5fvp.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "45.0.0"
                },
                {
                  "fixed": "47.7.4"
                }
              ]
            }
          ],
          "package": {
            "name": "@ckeditor/ckeditor5-engine",
            "purl": "pkg:npm/%40ckeditor/ckeditor5-engine",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-rh54-vffm-5fvp/GHSA-rh54-vffm-5fvp.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "48.0.0"
                },
                {
                  "fixed": "48.5.1"
                }
              ]
            }
          ],
          "package": {
            "name": "ckeditor5",
            "purl": "pkg:npm/ckeditor5",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-rh54-vffm-5fvp/GHSA-rh54-vffm-5fvp.json"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "48.0.0"
                },
                {
                  "fixed": "48.5.1"
                }
              ]
            }
          ],
          "package": {
            "name": "@ckeditor/ckeditor5-engine",
            "purl": "pkg:npm/%40ckeditor/ckeditor5-engine",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-rh54-vffm-5fvp/GHSA-rh54-vffm-5fvp.json"
          }
        }
      ],
      "modified": "2026-10-27T21:15:04.796866053Z",
      "provider": "osv",
      "references": [
        "https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-rh54-vffm-5fvp",
        "https://github.com/ckeditor/ckeditor5/commit/4d9c5bb34f63cd956d15ccafbe584e14280c86a0",
        "https://github.com/ckeditor/ckeditor5/commit/a750e38635db6a18c5b11599c09f4fd702850423",
        "https://github.com/ckeditor/ckeditor5",
        "https://github.com/ckeditor/ckeditor5/releases/tag/v47.7.4",
        "https://github.com/ckeditor/ckeditor5/releases/tag/v48.5.1"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-79"
        ],
        "severity": "HIGH",
        "github_reviewed": true,
        "nvd_published_at": null,
        "github_reviewed_at": "2026-10-27T21:05:06Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-116688",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 486107,
  "published_at": "2026-10-27T21:05:06+00:00"
}