{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-8238", "assignerOrgId": "ff5b8ace-8b95-4078-9743-eac1ca5451de", "state": "PUBLISHED", "assignerShortName": "ConcreteCMS", "dateReserved": "2026-05-09T15:48:41.906Z", "datePublished": "2026-05-21T21:04:50.691Z", "dateUpdated": "2026-05-21T21:04:50.691Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "ff5b8ace-8b95-4078-9743-eac1ca5451de", "shortName": "ConcreteCMS", "dateUpdated": "2026-05-21T21:04:50.691Z"}, "title": "Concrete CMS 9.5.0 and below is vulnerable to IDOR in '/ccm/frontend/conversations/message_page' allowing unauthenticated read of any conversation message", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-862", "description": "CWE-862", "type": "CWE"}]}], "impacts": [{"capecId": "CAPEC-122", "descriptions": [{"lang": "en", "value": "CAPEC-122 Privilege Abuse"}]}], "affected": [{"vendor": "Concrete CMS", "product": "Concrete CMS", "collectionURL": "https://github.com/concretecms/concretecms", "repo": "https://github.com/concretecms/concretecms", "versions": [{"status": "affected", "version": "5.0", "lessThanOrEqual": "9.5.0", "versionType": "git"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "Concrete CMS 9.5.0 and below is vulnerable to IDOR.\u00a0The\u00a0'/ccm/frontend/conversations/message_page'\u00a0endpoint returns the full content of any conversation message. An unauthenticated attacker can enumerate all conversation messages, including messages from restricted pages, member-only areas, and the moderation queue. File attachments with download URLs are also exposed.\u00a0The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of\u00a06.3 with Vector\u00a0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Tristan Madani for reporting.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "Concrete CMS 9.5.0 and below is vulnerable to IDOR.&nbsp;<span>The&nbsp;</span>'/ccm/frontend/conversations/message_page'<span>&nbsp;endpoint returns the full content of any conversation message. An unauthenticated attacker can enumerate all conversation messages, including messages from restricted pages, member-only areas, and the moderation queue. File attachments with download URLs are also exposed.&nbsp;</span>The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of&nbsp;6.3 with Vector&nbsp;CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Tristan Madani for reporting.&nbsp;"}]}], "references": [{"url": "https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes", "tags": ["release-notes"]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "MEDIUM", "baseScore": 6.3, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"}}], "credits": [{"lang": "en", "value": "Tristan Madani", "type": "finder"}], "source": {"defect": ["HackerOne"], "advisory": "https://hackerone.com/reports/3611476", "discovery": "EXTERNAL"}, "x_generator": {"engine": "Vulnogram 1.0.2"}}}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "Concrete CMS 9.5.0 and below is vulnerable to IDOR.\u00a0The\u00a0'/ccm/frontend/conversations/message_page'\u00a0endpoint returns the full content of any conversation message. An unauthenticated attacker can enumerate all conversation messages, including messages from restricted pages, member-only areas, and the moderation queue. File attachments with download URLs are also exposed.\u00a0The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of\u00a06.3 with Vector\u00a0CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N. Thanks Tristan Madani for reporting."}], "id": "CVE-2026-8238", "lastModified": "2026-05-21T22:16:49.893", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "ff5b8ace-8b95-4078-9743-eac1ca5451de", "type": "Secondary"}]}, "published": "2026-05-21T22:16:49.893", "references": [{"source": "ff5b8ace-8b95-4078-9743-eac1ca5451de", "url": "https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes"}], "sourceIdentifier": "ff5b8ace-8b95-4078-9743-eac1ca5451de", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-862"}], "source": "ff5b8ace-8b95-4078-9743-eac1ca5451de", "type": "Secondary"}]}

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[5.0,9.5.0]"}}], "enrichment": {"confidence": 98.0, "confidence_source": "matching", "scores": [{"score": 98.0, "source": "matching"}]}, "original": {"product": "Concrete CMS", "source": "cna", "vendor": "Concrete CMS"}, "product": "concrete_cms", "vendor": "concretecms"}], "created": "2026-05-21T22:30:20.374823+00:00", "updated": "2026-05-21T22:30:20.781263+00:00", "vendors": ["concretecms", "concretecms$PRODUCT$concrete_cms"]}