[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fh4mKYa7KyEEiXgwsOaJXet3c6APcuzHiZWiCLBvlbjA":3,"g5a-risk:CVE-2021-31535":205},{"success":4,"data":5,"meta":203},true,{"cveId":6,"title":7,"description":8,"shortDescription":9,"publishedDate":10,"lastModified":11,"cvssScore":12,"cvssVector":13,"cvssMetrics":14,"epssScore":39,"epssPercentile":27,"epssTimeSeries":40,"severity":41,"affectedProducts":42,"affectedProductsCount":56,"references":57,"referencesCount":131,"weaknesses":132,"weaknessesCount":141,"isActivelyExploited":142,"cisaInfo":27,"otxData":27,"relatedBlogPosts":143,"seoMetadata":144,"configurations":169,"relatedVendorCves":187,"notableEvents":188},"CVE-2021-31535","What is CVE-2021-31535?","LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code. The libX11 XLookupColor request (intended for server-side color lookup) contains a flaw allowing a client to send color-name requests with a name longer than the maximum size allowed by the protocol (and also longer than the maximum packet size for normal-sized packets). The user-controlled data exceeding the maximum size is then interpreted by the server as additional X protocol requests and executed, e.g., to disable X server authorization completely. For example, if the victim encounters malicious terminal control sequences for color codes, then the attacker may be able to take full control of the running graphical session.","LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code. The libX11 XLookupColor request (inten...","2021-05-27T13:15:08.24","2023-11-07T03:34:58.383",9.8,"CVSS:3.1\u002FAV:N\u002FAC:L\u002FPR:N\u002FUI:N\u002FS:U\u002FC:H\u002FI:H\u002FA:H",{"CVSSMetricV31":15,"CVSSMetricV30":27,"CVSSMetricV2":30,"CVSSMetricV40":27},[16],{"Source":17,"Type":18,"CVSSData":19,"ExploitabilityScore":28,"ImpactScore":29},"nvd@nist.gov","Primary",{"Version":20,"VectorString":13,"AttackVector":21,"AttackComplexity":22,"PrivilegesRequired":23,"UserInteraction":23,"Scope":24,"ConfidentialityImpact":25,"IntegrityImpact":25,"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","CRITICAL",null,3.9,5.9,[31],{"Source":17,"Type":18,"CVSSData":32,"BaseSeverity":25,"ExploitabilityScore":37,"ImpactScore":38,"ACInsufInfo":27,"ObtainAllPrivilege":27,"ObtainUserPrivilege":27,"ObtainOtherPrivilege":27,"UserInteractionRequired":27},{"Version":33,"VectorString":34,"AccessVector":21,"AccessComplexity":22,"Authentication":23,"ConfidentialityImpact":35,"IntegrityImpact":35,"AvailabilityImpact":35,"BaseScore":36,"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:N\u002FC:P\u002FI:P\u002FA:P","PARTIAL",7.5,10,6.4,0.10634,[39,39,39,39,39,39,39],"Critical",[43,48,51],{"vendor":44,"product":45,"version":46,"criteria":47,"vulnerable":4},"x.org","libx11","*","cpe:2.3:a:x.org:libx11:*:*:*:*:*:*:*:*",{"vendor":44,"product":49,"version":46,"criteria":50,"vulnerable":4},"x_window_system","cpe:2.3:o:x.org:x_window_system:*:*:*:*:*:*:*:*",{"vendor":52,"product":53,"version":54,"criteria":55,"vulnerable":4},"fedoraproject","fedora","33","cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",3,[58,65,70,74,78,82,85,88,91,95,99,102,107,111,115,119,122,125,128],{"url":59,"source":60,"tags":61},"http:\u002F\u002Fpacketstormsecurity.com\u002Ffiles\u002F162737\u002FlibX11-Insufficient-Length-Check-Injection.html","Packetstormsecurity",[62,63,64],"Exploit","Third Party Advisory","VDB Entry",{"url":66,"source":67,"tags":68},"http:\u002F\u002Fseclists.org\u002Ffulldisclosure\u002F2021\u002FMay\u002F52","Seclists",[69,63],"Mailing 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Advisory",{"url":108,"source":109,"tags":110},"https:\u002F\u002Fsecurity.gentoo.org\u002Fglsa\u002F202105-16","Gentoo",[63],{"url":112,"source":113,"tags":114},"https:\u002F\u002Fsecurity.netapp.com\u002Fadvisory\u002Fntap-20210813-0001\u002F","Netapp",[63],{"url":116,"source":117,"tags":118},"https:\u002F\u002Funparalleled.eu\u002Fblog\u002F2021\u002F20210518-using-xterm-to-navigate-the-huge-color-space\u002F","Unparalleled",[62,63],{"url":120,"source":117,"tags":121},"https:\u002F\u002Funparalleled.eu\u002Fpublications\u002F2021\u002Fadvisory-unpar-2021-1.txt",[62,63],{"url":123,"source":93,"tags":124},"https:\u002F\u002Fwww.debian.org\u002Fsecurity\u002F2021\u002Fdsa-4920",[63],{"url":126,"source":72,"tags":127},"https:\u002F\u002Fwww.openwall.com\u002Flists\u002Foss-security\u002F2021\u002F05\u002F18\u002F2",[69,63],{"url":129,"source":72,"tags":130},"https:\u002F\u002Fwww.openwall.com\u002Flists\u002Foss-security\u002F2021\u002F05\u002F18\u002F3",[69,63],19,[133],{"id":134,"name":135,"description":136,"extendedDescription":137,"status":138,"abstraction":139,"structure":140},"CWE-120","Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')","The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.","A buffer overflow condition exists when a product attempts to put more data in a buffer than it can hold, or when it attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the \"classic\" case in which the product copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.","Incomplete","Base","Simple",1,false,[],{"title":145,"metaDescription":146,"keywords":147,"canonicalUrl":148,"structuredData":149},"What is CVE-2021-31535? Vulnerability Analysis | Security Advisory | Precursor Intelligence","Comprehensive analysis of CVE-2021-31535, a critical severity cyber security vulnerability from 2021. LookupCol.c in X.Org X through X11R7.7 and libX11 befor...","CVE-2021-31535, CVE-2021-31535 vulnerability, CVE-2021-31535 security, critical severity vulnerability, cybersecurity, vulnerability analysis, security advisory, CVE database, threat intelligence, security research, vulnerability assessment, cyber threats, 2021, CVSS score, exploit, patch, remediation, x.org security, fedoraproject security, libx11 vulnerability, x_window_system vulnerability, fedora vulnerability","\u002Fwhat-is\u002Fcve-2021-31535",{"@context":150,"@type":151,"headline":145,"description":146,"datePublished":10,"dateModified":11,"author":152,"publisher":156,"about":160,"mainEntityOfPage":164,"articleSection":167,"keywords":168},"https:\u002F\u002Fschema.org","TechArticle",{"@type":153,"name":154,"url":155},"Organization","Precursor Intelligence","https:\u002F\u002Fprecursorintelligence.com",{"@type":153,"name":154,"url":155,"logo":157},{"@type":158,"url":159},"ImageObject","https:\u002F\u002Fprecursorintelligence.com\u002Fimg\u002Flogos\u002Feplogo.png",{"@type":161,"name":6,"description":162,"additionalType":163},"Thing","Cybersecurity Vulnerability","https:\u002F\u002Fschema.org\u002FSoftwareBug",{"@type":165,"@id":166},"WebPage","https:\u002F\u002Fprecursorintelligence.com\u002Fwhat-is\u002Fcve-2021-31535","Cybersecurity","CVE-2021-31535, CVE-2021-31535 vulnerability, CVE-2021-31535 security, critical severity vulnerability, cybersecurity, vulnerability analysis, security advisory, CVE database, threat intelligence, security research",[170,181],{"Operator":27,"Negate":27,"Nodes":171},[172],{"Operator":173,"Negate":27,"CPEMatch":174},"OR",[175,178],{"Vulnerable":4,"Criteria":47,"MatchCriteriaID":176,"VersionStartExcluding":27,"VersionStartIncluding":27,"VersionEndExcluding":177,"VersionEndIncluding":27},"AC5EF16E-76E0-4A32-9CF8-272B013E9F9C","1.7.1",{"Vulnerable":4,"Criteria":50,"MatchCriteriaID":179,"VersionStartExcluding":27,"VersionStartIncluding":27,"VersionEndExcluding":27,"VersionEndIncluding":180},"856DA4F8-78C3-4FC3-BC21-CD1A3C98FFA4","x11r7.7",{"Operator":27,"Negate":27,"Nodes":182},[183],{"Operator":173,"Negate":27,"CPEMatch":184},[185],{"Vulnerable":4,"Criteria":55,"MatchCriteriaID":186,"VersionStartExcluding":27,"VersionStartIncluding":27,"VersionEndExcluding":27,"VersionEndIncluding":27},"E460AA51-FCDA-46B9-AE97-E6676AA5E194",[],[189,196],{"id":190,"eventType":191,"eventTime":192,"details":193,"label":194,"color":195},"b7afd13e-c561-4541-929f-6c4c2aa40141","HIGH_EPSS_DELTA","2025-11-19T04:06:01.102079+00:00","Daily EPSS score increased by 0.173 on 2023-12-30","EPSS Score Increased","red",{"id":197,"eventType":198,"eventTime":199,"details":200,"label":201,"color":202},"cfee2c97-a91a-4a4d-9a55-986f03058a98","LOW_EPSS_DELTA","2025-11-22T04:05:49.037226+00:00","Daily EPSS score decreased by 0.173 on 2023-12-30","EPSS Score Decreased","green",{"lastModified":11,"cacheTime":204,"version":33},1792259296129,{"score":206,"band":207,"action":208,"scoredAt":209},63,"Medium","Plan remediation","2026-10-16T06:51:13.851053+00:00"]