{
    "CVE_data_meta": {
        "ASSIGNER": "security-advisories@github.com",
        "ID": "CVE-2021-21391",
        "STATE": "PUBLIC",
        "TITLE": "Regular expression Denial of Service in multiple packages"
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "product": {
                        "product_data": [
                            {
                                "product_name": "ckeditor5",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_value": "< 27.0.0"
                                        }
                                    ]
                                }
                            }
                        ]
                    },
                    "vendor_name": "ckeditor"
                }
            ]
        }
    },
    "data_format": "MITRE",
    "data_type": "CVE",
    "data_version": "4.0",
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "CKEditor 5 provides a WYSIWYG editing solution. This CVE affects the following npm packages: ckeditor5-engine, ckeditor5-font, ckeditor5-image, ckeditor5-list, ckeditor5-markdown-gfm, ckeditor5-media-embed, ckeditor5-paste-from-office, and ckeditor5-widget. Following an internal audit, a regular expression denial of service (ReDoS) vulnerability has been discovered in multiple CKEditor 5 packages. The vulnerability allowed to abuse particular regular expressions, which could cause a significant performance drop resulting in a browser tab freeze. It affects all users using the CKEditor 5 packages listed above at version <= 26.0.0. The problem has been recognized and patched. The fix will be available in version 27.0.0."
            }
        ]
    },
    "impact": {
        "cvss": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
            "version": "3.1"
        }
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "CWE-400: Uncontrolled Resource Consumption"
                    }
                ]
            }
        ]
    },
    "references": {
        "reference_data": [
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm"
            },
            {
                "name": "https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj",
                "refsource": "CONFIRM",
                "url": "https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-engine",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-engine"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-font",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-font"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-image",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-image"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-list",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-list"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-media-embed",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-media-embed"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-paste-from-office",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-paste-from-office"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-widget",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-widget"
            }
        ]
    },
    "source": {
        "advisory": "GHSA-3rh3-wfr4-76mj",
        "discovery": "UNKNOWN"
    }
}