{"id":"CVE-2021-21391","state":"PUBLISHED","title":"Regular expression Denial of Service in multiple packages","description":"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.","publishedAt":"2021-04-29T00:20:19.000Z","updatedAt":"2024-08-03T18:09:15.938Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["ckeditor ckeditor5"],"affected":[{"vendor":"ckeditor","product":"ckeditor5","versions":[{"version":"< 27.0.0","status":"affected"}]}],"references":["https://www.npmjs.com/package/%40ckeditor/ckeditor5-markdown-gfm","https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj","https://www.npmjs.com/package/%40ckeditor/ckeditor5-engine","https://www.npmjs.com/package/%40ckeditor/ckeditor5-font","https://www.npmjs.com/package/%40ckeditor/ckeditor5-image","https://www.npmjs.com/package/%40ckeditor/ckeditor5-list","https://www.npmjs.com/package/%40ckeditor/ckeditor5-media-embed","https://www.npmjs.com/package/%40ckeditor/ckeditor5-paste-from-office","https://www.npmjs.com/package/%40ckeditor/ckeditor5-widget"],"weaknesses":["CWE-400"],"ingestedAt":"2026-10-29T19:47:59.168Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/21xxx/CVE-2021-21391.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2021-21391","state":"PUBLISHED","datePublished":"2021-04-29T00:20:19.000Z","dateUpdated":"2024-08-03T18:09:15.938Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2020-12-22T00:00:00.000Z"},"containers":{"cna":{"title":"Regular expression Denial of Service in multiple packages","descriptions":[{"lang":"en","value":"CKEditor 5 provides a WYSIWYG editing solution. 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The fix will be available in version 27.0.0."}],"affected":[{"vendor":"ckeditor","product":"ckeditor5","versions":[{"version":"< 27.0.0","status":"affected"}]}],"references":[{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-markdown-gfm","tags":["x_refsource_MISC"]},{"url":"https://github.com/ckeditor/ckeditor5/security/advisories/GHSA-3rh3-wfr4-76mj","tags":["x_refsource_CONFIRM"]},{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-engine","tags":["x_refsource_MISC"]},{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-font","tags":["x_refsource_MISC"]},{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-image","tags":["x_refsource_MISC"]},{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-list","tags":["x_refsource_MISC"]},{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-media-embed","tags":["x_refsource_MISC"]},{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-paste-from-office","tags":["x_refsource_MISC"]},{"url":"https://www.npmjs.com/package/%40ckeditor/ckeditor5-widget","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"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"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","description":"CWE-400: Uncontrolled Resource Consumption","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","dateUpdated":"2021-04-29T00:20:19.000Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa"},"source":{"advisory":"GHSA-3rh3-wfr4-76mj","discovery":"UNKNOWN"},"x_legacyV4Record":{"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. 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