[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fJhH8f12dBJQGyQarkTpLWnI3ONHKWRFdn2w8vttSUHM":3,"g5a-risk:CVE-2021-21254":118},{"success":4,"data":5,"meta":116},true,{"cveId":6,"title":7,"description":8,"shortDescription":9,"publishedDate":10,"lastModified":11,"cvssScore":12,"cvssVector":13,"cvssMetrics":14,"epssScore":44,"epssPercentile":27,"epssTimeSeries":45,"severity":46,"affectedProducts":47,"affectedProductsCount":53,"references":54,"referencesCount":68,"weaknesses":69,"weaknessesCount":53,"isActivelyExploited":78,"cisaInfo":27,"otxData":27,"relatedBlogPosts":79,"seoMetadata":80,"configurations":105,"relatedVendorCves":114,"notableEvents":115},"CVE-2021-21254","What is CVE-2021-21254?","CKEditor 5 is an open source rich text editor framework with a modular architecture. The CKEditor 5 Markdown plugin (@ckeditor\u002Fckeditor5-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 \u003C= 24.0.0. The problem has been recognized and patched. The fix will be available in version 25.0.0.","CKEditor 5 is an open source rich text editor framework with a modular architecture. The CKEditor 5 Markdown plugin (@ckeditor\u002Fckeditor5-markdown-gfm) before...","2021-01-29T22:15:14.797","2023-11-07T03:29:41.453",6.5,"CVSS:3.1\u002FAV:N\u002FAC:L\u002FPR:L\u002FUI:N\u002FS:U\u002FC:N\u002FI:N\u002FA:H",{"CVSSMetricV31":15,"CVSSMetricV30":27,"CVSSMetricV2":34,"CVSSMetricV40":27},[16,30],{"Source":17,"Type":18,"CVSSData":19,"ExploitabilityScore":28,"ImpactScore":29},"nvd@nist.gov","Primary",{"Version":20,"VectorString":13,"AttackVector":21,"AttackComplexity":22,"PrivilegesRequired":22,"UserInteraction":23,"Scope":24,"ConfidentialityImpact":23,"IntegrityImpact":23,"AvailabilityImpact":25,"BaseScore":12,"BaseSeverity":26,"ExploitCodeMaturity":27,"RemediationLevel":27,"ReportConfidence":27,"TemporalScore":27,"TemporalSeverity":27,"ConfidentialityRequirement":27,"IntegrityRequirement":27,"AvailabilityRequirement":25,"ModifiedAttackVector":27,"ModifiedAttackComplexity":27,"ModifiedPrivilegesRequired":27,"ModifiedUserInteraction":27,"ModifiedScope":27,"ModifiedConfidentialityImpact":27,"ModifiedIntegrityImpact":27,"ModifiedAvailabilityImpact":27,"EnvironmentalScore":27,"EnvironmentalSeverity":27},"3.1","NETWORK","LOW","NONE","UNCHANGED","HIGH","MEDIUM",null,2.8,3.6,{"Source":31,"Type":32,"CVSSData":33,"ExploitabilityScore":28,"ImpactScore":29},"a0819718-46f1-4df5-94e2-005712e83aaa","Secondary",{"Version":20,"VectorString":13,"AttackVector":21,"AttackComplexity":22,"PrivilegesRequired":22,"UserInteraction":23,"Scope":24,"ConfidentialityImpact":23,"IntegrityImpact":23,"AvailabilityImpact":25,"BaseScore":12,"BaseSeverity":26,"ExploitCodeMaturity":27,"RemediationLevel":27,"ReportConfidence":27,"TemporalScore":27,"TemporalSeverity":27,"ConfidentialityRequirement":27,"IntegrityRequirement":27,"AvailabilityRequirement":25,"ModifiedAttackVector":27,"ModifiedAttackComplexity":27,"ModifiedPrivilegesRequired":27,"ModifiedUserInteraction":27,"ModifiedScope":27,"ModifiedConfidentialityImpact":27,"ModifiedIntegrityImpact":27,"ModifiedAvailabilityImpact":27,"EnvironmentalScore":27,"EnvironmentalSeverity":27},[35],{"Source":17,"Type":18,"CVSSData":36,"BaseSeverity":26,"ExploitabilityScore":42,"ImpactScore":43,"ACInsufInfo":27,"ObtainAllPrivilege":27,"ObtainUserPrivilege":27,"ObtainOtherPrivilege":27,"UserInteractionRequired":27},{"Version":37,"VectorString":38,"AccessVector":21,"AccessComplexity":22,"Authentication":39,"ConfidentialityImpact":23,"IntegrityImpact":23,"AvailabilityImpact":40,"BaseScore":41,"BaseSeverity":27,"Exploitability":27,"RemediationLevel":27,"ReportConfidence":27,"TemporalScore":27,"CollateralDamagePotential":27,"TargetDistribution":27,"ConfidentialityRequirement":27,"IntegrityRequirement":27,"AvailabilityRequirement":27,"EnvironmentalScore":27},"2.0","AV:N\u002FAC:L\u002FAu:S\u002FC:N\u002FI:N\u002FA:P","SINGLE","PARTIAL",4,8,2.9,0.01792,[44,44,44,44,44,44,44],"Medium",[48],{"vendor":49,"product":50,"version":51,"criteria":52,"vulnerable":4},"ckeditor","ckeditor5","*","cpe:2.3:a:ckeditor:ckeditor5:*:*:*:*:*:*:*:*",1,[55,61,64],{"url":56,"source":57,"tags":58},"https:\u002F\u002Fgithub.com\u002Fckeditor\u002Fckeditor5\u002Freleases\u002Ftag\u002Fv25.0.0","GitHub",[59,60],"Release Notes","Third Party Advisory",{"url":62,"source":57,"tags":63},"https:\u002F\u002Fgithub.com\u002Fckeditor\u002Fckeditor5\u002Fsecurity\u002Fadvisories\u002FGHSA-hgmg-hhc8-g5wr",[60],{"url":65,"source":66,"tags":67},"https:\u002F\u002Fwww.npmjs.com\u002Fpackage\u002F%40ckeditor\u002Fckeditor5-markdown-gfm","Npmjs",[],3,[70],{"id":71,"name":72,"description":73,"extendedDescription":74,"status":75,"abstraction":76,"structure":77},"CWE-400","Uncontrolled Resource Consumption","The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.","Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system.\nThere are at least three distinct scenarios which can commonly lead to resource exhaustion:\nResource exhaustion problems are often result due to an incorrect implementation of the following situations:","Draft","Class","Simple",false,[],{"title":81,"metaDescription":82,"keywords":83,"canonicalUrl":84,"structuredData":85},"What is CVE-2021-21254? Vulnerability Analysis | Security Advisory | Precursor Intelligence","Comprehensive analysis of CVE-2021-21254, a medium severity cyber security vulnerability from 2021. CKEditor 5 is an open source rich text editor framework w...","CVE-2021-21254, CVE-2021-21254 vulnerability, CVE-2021-21254 security, medium severity vulnerability, cybersecurity, vulnerability analysis, security advisory, CVE database, threat intelligence, security research, vulnerability assessment, cyber threats, 2021, CVSS score, exploit, patch, remediation, ckeditor security, ckeditor5 vulnerability","\u002Fwhat-is\u002Fcve-2021-21254",{"@context":86,"@type":87,"headline":81,"description":82,"datePublished":10,"dateModified":11,"author":88,"publisher":92,"about":96,"mainEntityOfPage":100,"articleSection":103,"keywords":104},"https:\u002F\u002Fschema.org","TechArticle",{"@type":89,"name":90,"url":91},"Organization","Precursor Intelligence","https:\u002F\u002Fprecursorintelligence.com",{"@type":89,"name":90,"url":91,"logo":93},{"@type":94,"url":95},"ImageObject","https:\u002F\u002Fprecursorintelligence.com\u002Fimg\u002Flogos\u002Feplogo.png",{"@type":97,"name":6,"description":98,"additionalType":99},"Thing","Cybersecurity Vulnerability","https:\u002F\u002Fschema.org\u002FSoftwareBug",{"@type":101,"@id":102},"WebPage","https:\u002F\u002Fprecursorintelligence.com\u002Fwhat-is\u002Fcve-2021-21254","Cybersecurity","CVE-2021-21254, CVE-2021-21254 vulnerability, CVE-2021-21254 security, medium severity vulnerability, cybersecurity, vulnerability analysis, security advisory, CVE database, threat intelligence, security research",[106],{"Operator":27,"Negate":27,"Nodes":107},[108],{"Operator":109,"Negate":27,"CPEMatch":110},"OR",[111],{"Vulnerable":4,"Criteria":52,"MatchCriteriaID":112,"VersionStartExcluding":27,"VersionStartIncluding":27,"VersionEndExcluding":113,"VersionEndIncluding":27},"8B47943C-76FE-4852-86F0-14CA6F0BD30D","25.0.0",[],[],{"lastModified":11,"cacheTime":117,"version":37},1792265556971,{"score":119,"band":120,"action":121,"scoredAt":122},23,"Low","Monitor","2026-10-16T06:50:23.965039+00:00"]