diff --git a/2021/21xxx/CVE-2021-21254.json b/2021/21xxx/CVE-2021-21254.json
index 0b7fff7debb..27ff734613d 100644
--- a/2021/21xxx/CVE-2021-21254.json
+++ b/2021/21xxx/CVE-2021-21254.json
@@ -1,18 +1,93 @@
 {
-    "data_type": "CVE",
-    "data_format": "MITRE",
-    "data_version": "4.0",
     "CVE_data_meta": {
+        "ASSIGNER": "security-advisories@github.com",
         "ID": "CVE-2021-21254",
-        "ASSIGNER": "cve@mitre.org",
-        "STATE": "RESERVED"
+        "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": "** RESERVED ** This candidate has been reserved by an organization or individual that will use it when announcing a new security problem. When the candidate has been publicized, the details for this candidate will be provided."
+                "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. \n\nThe 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"
     }
 }
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