{
    "CVE_data_meta": {
        "ASSIGNER": "security-advisories@github.com",
        "ID": "CVE-2021-21254",
        "STATE": "PUBLIC",
        "TITLE": "Regular expression Denial of Service in Markdown plugin"
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "product": {
                        "product_data": [
                            {
                                "product_name": "ckeditor5",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_value": "< 25.0.0"
                                        }
                                    ]
                                }
                            }
                        ]
                    },
                    "vendor_name": "ckeditor"
                }
            ]
        }
    },
    "data_format": "MITRE",
    "data_type": "CVE",
    "data_version": "4.0",
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "CKEditor 5 is an open source rich text editor framework with a modular architecture. The CKEditor 5 Markdown plugin (@ckeditor/ckeditor5-markdown-gfm) before version 25.0.0 has a regex denial of service (ReDoS) vulnerability. The vulnerability allowed to abuse link recognition regular expression, which could cause a significant performance drop resulting in browser tab freeze. It affects all users using CKEditor 5 Markdown plugin at version <= 24.0.0. The problem has been recognized and patched. The fix will be available in version 25.0.0."
            }
        ]
    },
    "impact": {
        "cvss": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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://github.com/ckeditor/ckeditor5/security/advisories/GHSA-hgmg-hhc8-g5wr",
                "refsource": "CONFIRM",
                "url": "https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-hgmg-hhc8-g5wr"
            },
            {
                "name": "https://github.com/ckeditor/ckeditor5/releases/tag/v25.0.0",
                "refsource": "MISC",
                "url": "https://github.com/ckeditor/ckeditor5/releases/tag/v25.0.0"
            },
            {
                "name": "https://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm",
                "refsource": "MISC",
                "url": "https://www.npmjs.com/package/@ckeditor/ckeditor5-markdown-gfm"
            }
        ]
    },
    "source": {
        "advisory": "GHSA-hgmg-hhc8-g5wr",
        "discovery": "UNKNOWN"
    }
}